CWE-787
Allowed-with-ReviewOut-of-bounds Write
Abstraction: Base · Status: Draft
The product writes data past the end, or before the beginning, of the intended buffer.
15138 vulnerabilities reference this CWE, most recent first.
GHSA-2PX6-897Q-9WVW
Vulnerability from github – Published: 2022-05-24 19:04 – Updated: 2022-05-24 19:04A vulnerability has been identified in Simcenter Femap 2020.2 (All versions < V2020.2.MP3), Simcenter Femap 2021.1 (All versions < V2021.1.MP3). The femap.exe application lacks proper validation of user-supplied data when parsing FEMAP files. This could result in an out of bounds write past the end of an allocated structure, a different vulnerability than CVE-2021-27387. An attacker could leverage this vulnerability to execute code in the context of the current process. (ZDI-CAN-12820)
{
"affected": [],
"aliases": [
"CVE-2021-27399"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-06-08T20:15:00Z",
"severity": "HIGH"
},
"details": "A vulnerability has been identified in Simcenter Femap 2020.2 (All versions \u003c V2020.2.MP3), Simcenter Femap 2021.1 (All versions \u003c V2021.1.MP3). The femap.exe application lacks proper validation of user-supplied data when parsing FEMAP files. This could result in an out of bounds write past the end of an allocated structure, a different vulnerability than CVE-2021-27387. An attacker could leverage this vulnerability to execute code in the context of the current process. (ZDI-CAN-12820)",
"id": "GHSA-2px6-897q-9wvw",
"modified": "2022-05-24T19:04:17Z",
"published": "2022-05-24T19:04:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-27399"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/pdf/ssa-133038.pdf"
},
{
"type": "WEB",
"url": "https://www.zerodayinitiative.com/advisories/ZDI-21-781"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-2Q26-8G6X-6RR4
Vulnerability from github – Published: 2025-07-04 15:31 – Updated: 2025-12-18 21:31In the Linux kernel, the following vulnerability has been resolved:
media: vivid: Change the siize of the composing
syzkaller found a bug:
BUG: KASAN: vmalloc-out-of-bounds in tpg_fill_plane_pattern drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2608 [inline] BUG: KASAN: vmalloc-out-of-bounds in tpg_fill_plane_buffer+0x1a9c/0x5af0 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2705 Write of size 1440 at addr ffffc9000d0ffda0 by task vivid-000-vid-c/5304
CPU: 0 UID: 0 PID: 5304 Comm: vivid-000-vid-c Not tainted 6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106 tpg_fill_plane_pattern drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2608 [inline] tpg_fill_plane_buffer+0x1a9c/0x5af0 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2705 vivid_fillbuff drivers/media/test-drivers/vivid/vivid-kthread-cap.c:470 [inline] vivid_thread_vid_cap_tick+0xf8e/0x60d0 drivers/media/test-drivers/vivid/vivid-kthread-cap.c:629 vivid_thread_vid_cap+0x8aa/0xf30 drivers/media/test-drivers/vivid/vivid-kthread-cap.c:767 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
The composition size cannot be larger than the size of fmt_cap_rect. So execute v4l2_rect_map_inside() even if has_compose_cap == 0.
{
"affected": [],
"aliases": [
"CVE-2025-38226"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-04T14:15:31Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: vivid: Change the siize of the composing\n\nsyzkaller found a bug:\n\nBUG: KASAN: vmalloc-out-of-bounds in tpg_fill_plane_pattern drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2608 [inline]\nBUG: KASAN: vmalloc-out-of-bounds in tpg_fill_plane_buffer+0x1a9c/0x5af0 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2705\nWrite of size 1440 at addr ffffc9000d0ffda0 by task vivid-000-vid-c/5304\n\nCPU: 0 UID: 0 PID: 5304 Comm: vivid-000-vid-c Not tainted 6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #0\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\n\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0x169/0x550 mm/kasan/report.c:489\n kasan_report+0x143/0x180 mm/kasan/report.c:602\n kasan_check_range+0x282/0x290 mm/kasan/generic.c:189\n __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106\n tpg_fill_plane_pattern drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2608 [inline]\n tpg_fill_plane_buffer+0x1a9c/0x5af0 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:2705\n vivid_fillbuff drivers/media/test-drivers/vivid/vivid-kthread-cap.c:470 [inline]\n vivid_thread_vid_cap_tick+0xf8e/0x60d0 drivers/media/test-drivers/vivid/vivid-kthread-cap.c:629\n vivid_thread_vid_cap+0x8aa/0xf30 drivers/media/test-drivers/vivid/vivid-kthread-cap.c:767\n kthread+0x7a9/0x920 kernel/kthread.c:464\n ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n \u003c/TASK\u003e\n\nThe composition size cannot be larger than the size of fmt_cap_rect.\nSo execute v4l2_rect_map_inside() even if has_compose_cap == 0.",
"id": "GHSA-2q26-8g6x-6rr4",
"modified": "2025-12-18T21:31:34Z",
"published": "2025-07-04T15:31:10Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38226"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/00da1c767a6567e56f23dda586847586868ac064"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/57597d8db5bbda618ba2145b7e8a7e6f01b6a27e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5d89aa42534723400fefd46e26e053b9c382b4ee"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/635cea4f44c1ddae208666772c164eab5a6bce39"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/89b5ab822bf69867c3951dd0eb34b0314c38966b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c56398885716d97ee9bcadb2bc9663a8c1757a34"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f6b1b0f8ba0b61d8b511df5649d57235f230c135"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f83ac8d30c43fd902af7c84c480f216157b60ef0"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-2Q3R-VRPV-MQJV
Vulnerability from github – Published: 2022-05-24 19:11 – Updated: 2022-10-08 00:00Adobe Media Encoder version 15.2 (and earlier) is affected by a memory corruption vulnerability when parsing a specially crafted file. An unauthenticated attacker could leverage this vulnerability to achieve arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
{
"affected": [],
"aliases": [
"CVE-2021-36015"
],
"database_specific": {
"cwe_ids": [
"CWE-787",
"CWE-788"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-08-20T19:15:00Z",
"severity": "HIGH"
},
"details": "Adobe Media Encoder version 15.2 (and earlier) is affected by a memory corruption vulnerability when parsing a specially crafted file. An unauthenticated attacker could leverage this vulnerability to achieve arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.",
"id": "GHSA-2q3r-vrpv-mqjv",
"modified": "2022-10-08T00:00:20Z",
"published": "2022-05-24T19:11:43Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-36015"
},
{
"type": "WEB",
"url": "https://helpx.adobe.com/security/products/media-encoder/apsb21-43.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-2Q3X-MQW8-QF9R
Vulnerability from github – Published: 2022-05-24 17:41 – Updated: 2022-05-24 17:41An out-of-bounds write information disclosure vulnerability in Trend Micro Apex One (on-prem and SaaS), OfficeScan XG SP1, and Worry-Free Business Security (10.0 SP1 and Services) could allow a local attacker to escalate privileges on affected installations.
Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
{
"affected": [],
"aliases": [
"CVE-2021-25249"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-02-04T20:15:00Z",
"severity": "HIGH"
},
"details": "An out-of-bounds write information disclosure vulnerability in Trend Micro Apex One (on-prem and SaaS), OfficeScan XG SP1, and Worry-Free Business Security (10.0 SP1 and Services) could allow a local attacker to escalate privileges on affected installations.\n\nPlease note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.",
"id": "GHSA-2q3x-mqw8-qf9r",
"modified": "2022-05-24T17:41:09Z",
"published": "2022-05-24T17:41:09Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-25249"
},
{
"type": "WEB",
"url": "https://success.trendmicro.com/solution/000284202"
},
{
"type": "WEB",
"url": "https://success.trendmicro.com/solution/000284205"
},
{
"type": "WEB",
"url": "https://success.trendmicro.com/solution/000284206"
},
{
"type": "WEB",
"url": "https://www.zerodayinitiative.com/advisories/ZDI-21-119"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-2Q4R-FMFH-V6HP
Vulnerability from github – Published: 2023-05-09 03:30 – Updated: 2024-04-04 03:54In modem control device, there is a possible out of bounds write due to a missing bounds check. This could lead to local denial of service with System execution privileges needed.
{
"affected": [],
"aliases": [
"CVE-2022-48389"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-05-09T02:15:12Z",
"severity": "MODERATE"
},
"details": "In modem control device, there is a possible out of bounds write due to a missing bounds check. This could lead to local denial of service with System execution privileges needed.",
"id": "GHSA-2q4r-fmfh-v6hp",
"modified": "2024-04-04T03:54:52Z",
"published": "2023-05-09T03:30:41Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-48389"
},
{
"type": "WEB",
"url": "https://www.unisoc.com/en_us/secy/announcementDetail/1654776866982133761"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-2Q65-8X4G-WPPR
Vulnerability from github – Published: 2023-12-21 00:30 – Updated: 2023-12-22 21:30Tenda i29 v1.0 V1.0.0.5 was discovered to contain a buffer overflow via the rebootTime parameter in the sysScheduleRebootSet function.
{
"affected": [],
"aliases": [
"CVE-2023-50990"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-12-20T22:15:35Z",
"severity": "CRITICAL"
},
"details": "Tenda i29 v1.0 V1.0.0.5 was discovered to contain a buffer overflow via the rebootTime parameter in the sysScheduleRebootSet function.",
"id": "GHSA-2q65-8x4g-wppr",
"modified": "2023-12-22T21:30:22Z",
"published": "2023-12-21T00:30:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-50990"
},
{
"type": "WEB",
"url": "https://github.com/ef4tless/vuln/blob/master/iot/i29/sysScheduleRebootSet.md"
},
{
"type": "WEB",
"url": "http://tenda.com"
}
],
"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"
}
]
}
GHSA-2Q86-2WW4-WC89
Vulnerability from github – Published: 2023-09-08 03:30 – Updated: 2024-04-04 07:33An issue was discovered in iscflashx64.sys 3.9.3.0 in Insyde H2OFFT 6.20.00. When handling IOCTL 0x22229a, the input used to allocate a buffer and copy memory is mishandled. This could cause memory corruption or a system crash.
{
"affected": [],
"aliases": [
"CVE-2021-33834"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-09-08T02:15:07Z",
"severity": "HIGH"
},
"details": "An issue was discovered in iscflashx64.sys 3.9.3.0 in Insyde H2OFFT 6.20.00. When handling IOCTL 0x22229a, the input used to allocate a buffer and copy memory is mishandled. This could cause memory corruption or a system crash.",
"id": "GHSA-2q86-2ww4-wc89",
"modified": "2024-04-04T07:33:39Z",
"published": "2023-09-08T03:30:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-33834"
},
{
"type": "WEB",
"url": "https://www.insyde.com/security-pledge"
},
{
"type": "WEB",
"url": "https://www.insyde.com/security-pledge/SA-2021004"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-2Q8V-3GQQ-4F8P
Vulnerability from github – Published: 2024-01-19 16:19 – Updated: 2024-10-10 14:46### Summary
concat built-in can write over the bounds of the memory buffer that was allocated for it and thus overwrite existing valid data. The root cause is that the build_IR for concat doesn't properly adhere to the API of copy functions (for >=0.3.2 the copy_bytes function).
A contract search was performed and no vulnerable contracts were found in production.
Tracked in issue https://github.com/vyperlang/vyper/issues/3737
Details
The build_IR allocates a new internal variable for the concatenation: https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/builtins/functions.py#L534-L550
Notice that the buffer is allocated for the maxlen + 1 word to actually hold the length of the array.
Later the copy_bytes function is used to copy the actual source arguments to the destination: https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/builtins/functions.py#L569-L572
The dst_data is defined via:
- data ptr - to skip the 1 word that holds the length
- offset - to skip the source arguments that were already written to the buffer
- the offset is increased via: ["set", ofst, ["add", ofst, arglen]], ie it is increased by the length of the source argument
Now, the copy_bytes function has multiple control flow paths, the following ones are of interest:
1) https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/codegen/core.py#L270-L273
2) https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/codegen/core.py#L301-L320
Note that the function itself contains the following note: https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/codegen/core.py#L245-L247
That is we can ask for a copy of 1B yet a whole word is copied.
Consider the first interesting path - if the dst_data's distance to the end of the concat data buffer is < 32B, the copy_op = STORE(dst, LOAD(src)) from copy_bytes will result in buffer overflow as it essentially will mstore to dst_data the mload of the source (mload will load whole word and the distance of the dst_data to the word boundary is <32B).
From the two mentioned paths in copy_bytes it can be seen that both sources from memory and storage can cause the corruption.
PoC
The main attack vector that was found was when the concat is inside an internal function. Suppose we have an external function that calls internal one. In such case the address space is divided such that the memory for the internal function is in lower portion of the adr space. As such the buffer overflow can overwrite valid data of the caller.
Here is a simple example:
#@version ^0.3.9
@internal
def bar() -> uint256:
sss: String[2] = concat("a", "b")
return 1
@external
def foo() -> int256:
a: int256 = -1
b: uint256 = self.bar()
return a
foo should clearly return -1, but it returns 452312848583266388373324160190187140051835877600158453279131187530910662655
-1 was used intentionally due to its bit structure but the value here is fairly irelevant. In this example during the second iteration of the for loop in the build_IR mload to dst+1 will be executed (because len('a') == 1), thus the function will write 1B over the bounds of the buffer. The string 'b' is stored such that its right-most byte is a zero byte. So a zero byte will be written over the bounds. So when -1 is considered it's left-most B will be overwritten to all 0. Therefore it can be seen: 452312848583266388373324160190187140051835877600158453279131187530910662655 == (2**248-1) will output True.
IR
If we look at the contract's IR (vyper --no optimize -f ir), we see:
# Line 30
/* a: int256 = -1 */ [mstore, 320, -1 <-1>],
And for the second iteration of the loop in concat:
len,
[mload, arg],
[seq,
[with,
src,
[add, arg, 32],
[with,
dst,
[add, [add, 256 <concat destination>, 32], concat_ofst],
[mstore, dst, [mload, src]]]],
[set, concat_ofst, [add, concat_ofst, len]]]]],
[mstore, 256 <concat destination>, concat_ofst],
256 <concat destination>]],
So the address of the int is 320.
The dst is defined as: [add, [add, 256 <concat destination>, 32], concat_ofst],.
In the second iteration the concat_ofst will be 1 because len('a)==1 so 256+32+1 = 289. Now this address will be mstored to - so the last mstored B will have the address 289+32=320 which clearly overlaps with the address of the int a.
PoC 2
Due to how immutables are handled, they can be corrupted too:
#@version ^0.3.9
i: immutable(int256)
@external
def __init__():
i = -1
s: String[2] = concat("a", "b")
@external
def foo() -> int256:
return i
Output of calling foo() = 452312848583266388373324160190187140051835877600158453279131187530910662655.
Impact
The buffer overflow can result in the change of semantics of the contract. The overflow is length-dependent and thus it might go unnoticed during contract testing.
However, certainly not all usages of concat will result in overwritten valid data as we require it to be in an internal function and close to the return statement where other memory allocations don't occur.
Concluding remarks
The bug based on the fast path in copy_bytes was likely introduced in: 548d35d720fb6fd8efbdc0ce525bed259a73f0b9. git bisect was used between v0.3.1 and v0.3.2, forge test was run and the test asserted that the function indeed returns -1.
For the general case, 0.3.0 and 0.3.1 are also affected.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.3.10"
},
"package": {
"ecosystem": "PyPI",
"name": "vyper"
},
"ranges": [
{
"events": [
{
"introduced": "0.3.0"
},
{
"fixed": "0.4.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-22419"
],
"database_specific": {
"cwe_ids": [
"CWE-120",
"CWE-787"
],
"github_reviewed": true,
"github_reviewed_at": "2024-01-19T16:19:51Z",
"nvd_published_at": "2024-01-18T19:15:10Z",
"severity": "HIGH"
},
"details": " ### Summary\n`concat` built-in can write over the bounds of the memory buffer that was allocated for it and thus overwrite existing valid data. The root cause is that the `build_IR` for `concat` doesn\u0027t properly adhere to the API of copy functions (for `\u003e=0.3.2` the `copy_bytes` function).\n\nA contract search was performed and no vulnerable contracts were found in production.\n\nTracked in issue https://github.com/vyperlang/vyper/issues/3737\n\n### Details\nThe `build_IR` allocates a new internal variable for the concatenation: https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/builtins/functions.py#L534-L550\n\nNotice that the buffer is allocated for the `maxlen` + 1 word to actually hold the length of the array.\n\nLater the `copy_bytes` function is used to copy the actual source arguments to the destination: https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/builtins/functions.py#L569-L572\n\nThe `dst_data` is defined via:\n- `data ptr` - to skip the 1 word that holds the length\n- `offset` - to skip the source arguments that were already written to the buffer\n - the `offset` is increased via: `[\"set\", ofst, [\"add\", ofst, arglen]]`, ie it is increased by the length of the source argument\n\nNow, the `copy_bytes` function has multiple control flow paths, the following ones are of interest:\n1) https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/codegen/core.py#L270-L273\n2) https://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/codegen/core.py#L301-L320\n\nNote that the function itself contains the following note: \nhttps://github.com/vyperlang/vyper/blob/3b310d5292c4d1448e673d7b3adb223f9353260e/vyper/codegen/core.py#L245-L247\n\nThat is we can ask for a copy of `1B` yet a whole word is copied.\n\nConsider the first interesting path - if the `dst_data`\u0027s distance to the end of the concat data buffer is `\u003c 32B`, the `copy_op = STORE(dst, LOAD(src))` from `copy_bytes` will result in buffer overflow as it essentially will `mstore` to `dst_data` the `mload` of the source (mload will load whole word and the distance of the `dst_data` to the word boundary is `\u003c32B`).\n\nFrom the two mentioned paths in `copy_bytes` it can be seen that both sources from memory and storage can cause the corruption.\n\n### PoC\nThe main attack vector that was found was when the `concat` is inside an `internal` function. Suppose we have an `external` function that calls `internal` one. In such case the address space is divided such that the memory for the internal function is in _lower_ portion of the adr space. As such the buffer overflow can overwrite _valid_ data of the caller.\n\nHere is a simple example:\n```python\n#@version ^0.3.9\n\n@internal\ndef bar() -\u003e uint256:\n sss: String[2] = concat(\"a\", \"b\") \n return 1\n\n\n@external\ndef foo() -\u003e int256:\n a: int256 = -1\n b: uint256 = self.bar()\n return a \n```\n\n`foo` should clearly return `-1`, but it returns `452312848583266388373324160190187140051835877600158453279131187530910662655`\n\n`-1` was used intentionally due to its bit structure but the value here is fairly irelevant. In this example during the second iteration of the for loop in the `build_IR` `mload` to `dst+1` will be executed (because len(\u0027a\u0027) == 1), thus the function will write `1B` over the bounds of the buffer. The string \u0027b\u0027 is stored such that its right-most byte is a zero byte. So a zero byte will be written over the bounds. So when `-1` is considered it\u0027s left-most B will be overwritten to all 0. Therefore it can be seen: `452312848583266388373324160190187140051835877600158453279131187530910662655 == (2**248-1)` will output `True`.\n\n#### IR\nIf we look at the contract\u0027s IR (vyper --no optimize -f ir), we see:\n```\n# Line 30\n /* a: int256 = -1 */ [mstore, 320, -1 \u003c-1\u003e],\n```\nAnd for the second iteration of the loop in concat:\n```\n len,\n [mload, arg],\n [seq,\n [with,\n src,\n [add, arg, 32],\n [with,\n dst,\n [add, [add, 256 \u003cconcat destination\u003e, 32], concat_ofst],\n [mstore, dst, [mload, src]]]],\n [set, concat_ofst, [add, concat_ofst, len]]]]],\n [mstore, 256 \u003cconcat destination\u003e, concat_ofst],\n 256 \u003cconcat destination\u003e]],\n```\nSo the address of the `int` is 320. \n\nThe `dst` is defined as: `[add, [add, 256 \u003cconcat destination\u003e, 32], concat_ofst],`.\nIn the second iteration the `concat_ofst` will be 1 because `len(\u0027a)==1` so `256+32+1 = 289`. Now this address will be `mstored` to - so the last mstored B will have the address `289+32=320` which clearly overlaps with the address of the `int a`.\n\n#### PoC 2\nDue to how `immutables` are handled, they can be corrupted too:\n```python\n#@version ^0.3.9\n\ni: immutable(int256)\n\n@external\ndef __init__():\n i = -1\n s: String[2] = concat(\"a\", \"b\")\n\n@external\ndef foo() -\u003e int256:\n return i\n```\n\nOutput of calling `foo()` = `452312848583266388373324160190187140051835877600158453279131187530910662655`.\n\n### Impact\nThe buffer overflow can result in the change of semantics of the contract. The overflow is length-dependent and thus it might go unnoticed during contract testing.\n\nHowever, certainly not all usages of `concat` will result in overwritten valid data as we require it to be in an `internal` function and close to the `return` statement where other memory allocations don\u0027t occur. \n\n### Concluding remarks\nThe bug based on the fast path in `copy_bytes` was likely introduced in: `548d35d720fb6fd8efbdc0ce525bed259a73f0b9`. `git bisect` was used between v0.3.1 and v0.3.2, `forge test` was run and the test asserted that the function indeed returns -1.\n\nFor the general case, `0.3.0` and `0.3.1` are also affected.",
"id": "GHSA-2q8v-3gqq-4f8p",
"modified": "2024-10-10T14:46:31Z",
"published": "2024-01-19T16:19:51Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/vyperlang/vyper/security/advisories/GHSA-2q8v-3gqq-4f8p"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-22419"
},
{
"type": "WEB",
"url": "https://github.com/vyperlang/vyper/issues/3737"
},
{
"type": "WEB",
"url": "https://github.com/vyperlang/vyper/commit/55e18f6d128b2da8986adbbcccf1cd59a4b9ad6f"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2024-103.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/vyperlang/vyper"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "concat built-in can corrupt memory in vyper"
}
GHSA-2Q8V-R2XR-C9XC
Vulnerability from github – Published: 2023-12-05 03:30 – Updated: 2023-12-05 03:30Memory Corruption in camera while installing a fd for a particular DMA buffer.
{
"affected": [],
"aliases": [
"CVE-2023-22383"
],
"database_specific": {
"cwe_ids": [
"CWE-416",
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-12-05T03:15:08Z",
"severity": "MODERATE"
},
"details": "Memory Corruption in camera while installing a fd for a particular DMA buffer.",
"id": "GHSA-2q8v-r2xr-c9xc",
"modified": "2023-12-05T03:30:22Z",
"published": "2023-12-05T03:30:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-22383"
},
{
"type": "WEB",
"url": "https://www.qualcomm.com/company/product-security/bulletins/december-2023-bulletin"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-2Q9F-HRWC-CQPX
Vulnerability from github – Published: 2022-02-25 00:01 – Updated: 2022-03-04 00:00TL-WR841Nv14_US_0.9.1_4.18 routers were discovered to contain a stack overflow in the function dm_fillObjByStr(). This vulnerability allows unauthenticated attackers to execute arbitrary code.
{
"affected": [],
"aliases": [
"CVE-2022-25073"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-02-24T15:15:00Z",
"severity": "CRITICAL"
},
"details": "TL-WR841Nv14_US_0.9.1_4.18 routers were discovered to contain a stack overflow in the function dm_fillObjByStr(). This vulnerability allows unauthenticated attackers to execute arbitrary code.",
"id": "GHSA-2q9f-hrwc-cqpx",
"modified": "2022-03-04T00:00:34Z",
"published": "2022-02-25T00:01:04Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-25073"
},
{
"type": "WEB",
"url": "https://github.com/EPhaha/IOT_vuln/tree/main/TP-Link/TL-WR841N"
}
],
"schema_version": "1.4.0",
"severity": []
}
Mitigation MIT-3
Strategy: Language Selection
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.
- Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
Mitigation MIT-4.1
Strategy: Libraries or Frameworks
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.
Mitigation MIT-10
Strategy: Environment Hardening
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
- D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
Mitigation MIT-9
- Consider adhering to the following rules when allocating and managing an application's memory:
- Double check that the buffer is as large as specified.
- When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string.
- Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space.
- If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.
Mitigation MIT-11
Strategy: Environment Hardening
- Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
- Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
- For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
Mitigation MIT-12
Strategy: Environment Hardening
- Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.
- For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].
Mitigation MIT-13
Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.
No CAPEC attack patterns related to this CWE.