PYSEC-2026-2998
Vulnerability from pysec - Published: 2026-07-13 15:19 - Updated: 2026-07-13 16:05
VLAI
Details
Summary
The fix for CVE-2026-33509 prevents setting storage_folder inside PKGDIR or userdir, but does NOT protect the Flask session directory (/tmp/pyLoad/flask). An authenticated attacker can set storage_folder to the session directory and download session files of other users via /files/get/, leading to account takeover.
Details
The fix in src/pyload/core/api/__init__.py:
directories = [PKGDIR, userdir]
if any(directories[0].startswith(d) for d in directories[1:]):
return # blocked
But the Flask session directory is:
session_storage_path = os.path.join(api.get_cachedir(), "flask")
# = /tmp/pyLoad/flask ← NOT blocked by fix
Attack Chain
- Attacker (admin) sets
storage_folder = /tmp/pyLoad/flask - Fix does NOT block this —
/tmp/pyLoad/flasknot insidePKGDIRoruserdir - Attacker requests
GET /files/get/<victim_session_filename> send_from_directory('/tmp/pyLoad/flask', session_file)serves victim's session- Attacker uses stolen session → Account Takeover
PoC
import os
PKGDIR = "/usr/lib/python3/dist-packages/pyload"
userdir = os.path.expanduser("~/.pyload")
session_dir = "/tmp/pyLoad/flask"
correct_case = lambda x: x
directories = [
correct_case(os.path.join(os.path.realpath(d), ""))
for d in [session_dir, PKGDIR, userdir]
]
blocked = any(directories[0].startswith(d) for d in directories[1:])
print(f"Fix blocks session_dir: {blocked}")
# Output: Fix blocks session_dir: False ← BYPASS CONFIRMED
Impact
Authenticated admin can steal sessions of other users → Account Takeover.
Suggested Fix
blocked_dirs = [PKGDIR, userdir, api.get_cachedir()]
directories = [
os.path.join(os.path.realpath(d), "")
for d in [value] + blocked_dirs
]
if any(directories[0].startswith(d) for d in directories[1:]):
return
Severity
6.5 (Medium)
Impacted products
| Name | purl | pyload-ng | pkg:pypi/pyload-ng |
|---|
Aliases
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "pyload-ng",
"purl": "pkg:pypi/pyload-ng"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "0.5.0b3.dev99"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.5.0a5.dev528",
"0.5.0a5.dev532",
"0.5.0a5.dev535",
"0.5.0a5.dev536",
"0.5.0a5.dev537",
"0.5.0a5.dev539",
"0.5.0a5.dev540",
"0.5.0a5.dev545",
"0.5.0a5.dev562",
"0.5.0a5.dev564",
"0.5.0a5.dev565",
"0.5.0a6.dev570",
"0.5.0a6.dev578",
"0.5.0a6.dev587",
"0.5.0a7.dev596",
"0.5.0a8.dev602",
"0.5.0a9.dev615",
"0.5.0a9.dev629",
"0.5.0a9.dev632",
"0.5.0a9.dev641",
"0.5.0a9.dev643",
"0.5.0a9.dev655",
"0.5.0a9.dev806",
"0.5.0b1.dev1",
"0.5.0b1.dev2",
"0.5.0b1.dev3",
"0.5.0b1.dev4",
"0.5.0b1.dev5",
"0.5.0b2.dev10",
"0.5.0b2.dev11",
"0.5.0b2.dev12",
"0.5.0b2.dev9",
"0.5.0b3.dev13",
"0.5.0b3.dev14",
"0.5.0b3.dev17",
"0.5.0b3.dev18",
"0.5.0b3.dev19",
"0.5.0b3.dev20",
"0.5.0b3.dev21",
"0.5.0b3.dev22",
"0.5.0b3.dev24",
"0.5.0b3.dev26",
"0.5.0b3.dev27",
"0.5.0b3.dev28",
"0.5.0b3.dev29",
"0.5.0b3.dev30",
"0.5.0b3.dev31",
"0.5.0b3.dev32",
"0.5.0b3.dev33",
"0.5.0b3.dev34",
"0.5.0b3.dev35",
"0.5.0b3.dev38",
"0.5.0b3.dev39",
"0.5.0b3.dev40",
"0.5.0b3.dev41",
"0.5.0b3.dev42",
"0.5.0b3.dev43",
"0.5.0b3.dev44",
"0.5.0b3.dev45",
"0.5.0b3.dev46",
"0.5.0b3.dev47",
"0.5.0b3.dev48",
"0.5.0b3.dev49",
"0.5.0b3.dev50",
"0.5.0b3.dev51",
"0.5.0b3.dev52",
"0.5.0b3.dev53",
"0.5.0b3.dev54",
"0.5.0b3.dev57",
"0.5.0b3.dev60",
"0.5.0b3.dev62",
"0.5.0b3.dev64",
"0.5.0b3.dev65",
"0.5.0b3.dev66",
"0.5.0b3.dev67",
"0.5.0b3.dev68",
"0.5.0b3.dev69",
"0.5.0b3.dev70",
"0.5.0b3.dev71",
"0.5.0b3.dev72",
"0.5.0b3.dev73",
"0.5.0b3.dev74",
"0.5.0b3.dev75",
"0.5.0b3.dev76",
"0.5.0b3.dev77",
"0.5.0b3.dev78",
"0.5.0b3.dev79",
"0.5.0b3.dev80",
"0.5.0b3.dev81",
"0.5.0b3.dev82",
"0.5.0b3.dev85",
"0.5.0b3.dev87",
"0.5.0b3.dev88",
"0.5.0b3.dev89",
"0.5.0b3.dev90",
"0.5.0b3.dev91",
"0.5.0b3.dev92",
"0.5.0b3.dev93",
"0.5.0b3.dev94",
"0.5.0b3.dev95",
"0.5.0b3.dev96",
"0.5.0b3.dev97",
"0.5.0b3.dev98",
"0.5.0b3.dev99"
]
}
],
"aliases": [
"CVE-2026-45306",
"GHSA-w727-595x-pc3r"
],
"details": "## Summary\nThe fix for CVE-2026-33509 prevents setting `storage_folder` inside `PKGDIR` or `userdir`, but does NOT protect the Flask session directory (`/tmp/pyLoad/flask`). An authenticated attacker can set `storage_folder` to the session directory and download session files of other users via `/files/get/`, leading to account takeover.\n\n## Details\n\nThe fix in `src/pyload/core/api/__init__.py`:\n\n```python\ndirectories = [PKGDIR, userdir]\nif any(directories[0].startswith(d) for d in directories[1:]):\n return # blocked\n```\n\nBut the Flask session directory is:\n```python\nsession_storage_path = os.path.join(api.get_cachedir(), \"flask\")\n# = /tmp/pyLoad/flask \u2190 NOT blocked by fix\n```\n\n## Attack Chain\n\n1. Attacker (admin) sets `storage_folder = /tmp/pyLoad/flask`\n2. Fix does NOT block this \u2014 `/tmp/pyLoad/flask` not inside `PKGDIR` or `userdir`\n3. Attacker requests `GET /files/get/\u003cvictim_session_filename\u003e`\n4. `send_from_directory(\u0027/tmp/pyLoad/flask\u0027, session_file)` serves victim\u0027s session\n5. Attacker uses stolen session \u2192 **Account Takeover**\n\n## PoC\n\n\u003cimg width=\"592\" height=\"408\" alt=\"POC\" src=\"https://github.com/user-attachments/assets/936b9f56-325b-437d-9edd-e0d5bb995187\" /\u003e\n\n```python\nimport os\n\nPKGDIR = \"/usr/lib/python3/dist-packages/pyload\"\nuserdir = os.path.expanduser(\"~/.pyload\")\nsession_dir = \"/tmp/pyLoad/flask\"\n\ncorrect_case = lambda x: x\ndirectories = [\n correct_case(os.path.join(os.path.realpath(d), \"\"))\n for d in [session_dir, PKGDIR, userdir]\n]\nblocked = any(directories[0].startswith(d) for d in directories[1:])\n\nprint(f\"Fix blocks session_dir: {blocked}\")\n# Output: Fix blocks session_dir: False \u2190 BYPASS CONFIRMED\n```\n\n## Impact\nAuthenticated admin can steal sessions of other users \u2192 Account Takeover.\n\n## Suggested Fix\n```python\nblocked_dirs = [PKGDIR, userdir, api.get_cachedir()]\ndirectories = [\n os.path.join(os.path.realpath(d), \"\")\n for d in [value] + blocked_dirs\n]\nif any(directories[0].startswith(d) for d in directories[1:]):\n return\n```",
"id": "PYSEC-2026-2998",
"modified": "2026-07-13T16:05:53.241689Z",
"published": "2026-07-13T15:19:05.979484Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/pyload/pyload/security/advisories/GHSA-w727-595x-pc3r"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45306"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-r7mc-x6x7-cqxx"
},
{
"type": "PACKAGE",
"url": "https://github.com/pyload/pyload"
},
{
"type": "PACKAGE",
"url": "https://pypi.org/project/pyload-ng"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-w727-595x-pc3r"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "pyLoad Has Incomplete Fix for CVE-2026-33509 -storage_folder Bypass via Session Directory in pyLoad"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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