GHSA-G8M3-Q9H2-QP8G
Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-22 18:30In the Linux kernel, the following vulnerability has been resolved:
ima: fix out-of-bounds read in xattr_verify()
The digest-length check in xattr_verify() mixes int and size_t:
if (xattr_len - sizeof(xattr_value->type) - hash_start >=
iint->ima_hash->length)
sizeof() yields size_t, so the usual arithmetic conversions promote the whole left-hand side to unsigned 64-bit before the subtraction runs. For a truncated xattr this underflows instead of going negative: a 1-byte IMA_XATTR_DIGEST_NG xattr (xattr_len == 1, hash_start == 1) turns "1 - 1 - 1" into SIZE_MAX, which is trivially >= ima_hash->length. The check then passes and the following memcmp() reads iint->ima_hash->length bytes starting past the end of the buffer vfs_getxattr_alloc() allocated for it.
Nothing upstream clamps xattr_len back into a safe range first: ima_get_hash_algo() only special-cases xattr_len < 2 to pick a default algorithm, and evm_verifyxattr() returns INTEGRITY_UNKNOWN rather than failing when no HMAC key is loaded, so a truncated security.ima value reaches the length check as-is.
Rewrite the comparison so every operand stays a signed int and no implicit conversion to size_t can occur.
{
"affected": [],
"aliases": [
"CVE-2026-74671"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-22T16:16:41Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nima: fix out-of-bounds read in xattr_verify()\n\nThe digest-length check in xattr_verify() mixes int and size_t:\n\n\tif (xattr_len - sizeof(xattr_value-\u003etype) - hash_start \u003e=\n\t\t\tiint-\u003eima_hash-\u003elength)\n\nsizeof() yields size_t, so the usual arithmetic conversions promote\nthe whole left-hand side to unsigned 64-bit before the subtraction\nruns. For a truncated xattr this underflows instead of going negative:\na 1-byte IMA_XATTR_DIGEST_NG xattr (xattr_len == 1, hash_start == 1)\nturns \"1 - 1 - 1\" into SIZE_MAX, which is trivially \u003e= ima_hash-\u003elength.\nThe check then passes and the following memcmp() reads\niint-\u003eima_hash-\u003elength bytes starting past the end of the buffer\nvfs_getxattr_alloc() allocated for it.\n\nNothing upstream clamps xattr_len back into a safe range first:\nima_get_hash_algo() only special-cases xattr_len \u003c 2 to pick a default\nalgorithm, and evm_verifyxattr() returns INTEGRITY_UNKNOWN rather than\nfailing when no HMAC key is loaded, so a truncated security.ima value\nreaches the length check as-is.\n\nRewrite the comparison so every operand stays a signed int and no\nimplicit conversion to size_t can occur.",
"id": "GHSA-g8m3-q9h2-qp8g",
"modified": "2026-08-22T18:30:28Z",
"published": "2026-08-22T18:30:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74671"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/27f3924061592d0ef6b04e16f48754b6cb6adf27"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5ff232d31106f45ac87c3b64e1d35a0667777797"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7e515b6c9aab452a4f0734bd7208e4e780e164ca"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a784b4732ac7e51862b9b210c2d8b2ab9e83568c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b6cb134707a2127d90a58d69dd818679cae8033c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/caeb105c15ea2431fa8da7ecfa242d0c68272426"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d823b5f4557083d1dd92096f796a78a2b1b06d10"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dd04114af0d451091f7b8cbd26d9e37d011e9131"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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