CVE-2026-74671
Full vulnerability record from the local CVENow database.
Description
In 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.
Severity
Not scored
CVSS score
Not available
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-08-22 16:16:41.063000
Last modified
2026-11-06 17:19:53.383000
View original CVE JSON
{
"id": "CVE-2026-74671",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-08-22T16:16:41.063",
"lastModified": "2026-11-06T17:19:53.383",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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->type) - hash_start >=\n\t\t\tiint->ima_hash->length)\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 >= ima_hash->length.\nThe check then passes and the following memcmp() reads\niint->ima_hash->length 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 < 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."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nima: solución a lectura fuera de límites en xattr_verify()\n\nLa comprobación de la longitud del digest en xattr_verify() mezcla int y size_t:\n\n\tif (xattr_len - sizeof(xattr_value -> type) - hash_start >=\n\t\t\tiint -> ima_hash -> length)\n\nsizeof() produce size_t, por lo que las conversiones aritméticas habituales promueven todo el lado izquierdo a unsigned de 64 bits antes de que se ejecute la resta. Para un xattr truncado, esto provoca un desbordamiento negativo (underflow) en lugar de volverse negativo: un xattr IMA_XATTR_DIGEST_NG de 1 byte (xattr_len == 1, hash_start == 1) convierte '1 - 1 - 1' en SIZE_MAX, lo cual es trivialmente >= ima_hash -> length. La comprobación entonces pasa y el siguiente memcmp() lee iint -> ima_hash -> length bytes comenzando más allá del final del búfer que vfs_getxattr_alloc() asignó para ello.\n\nNada en la cadena de desarrollo (upstream) restringe xattr_len a un rango seguro primero: ima_get_hash_algo() solo trata de forma especial los casos donde xattr_len < 2 para seleccionar un algoritmo predeterminado, y evm_verifyxattr() devuelve INTEGRITY_UNKNOWN en lugar de fallar cuando no se carga ninguna clave HMAC, por lo que un valor security.ima truncado llega a la comprobación de longitud tal cual.\n\nReescribir la comparación para que cada operando permanezca como un int con signo y no pueda ocurrir ninguna conversión implícita a size_t."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"security/integrity/ima/ima_appraise.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
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"versionType": "git",
"status": "affected"
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"status": "affected"
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},
{
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"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"security/integrity/ima/ima_appraise.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
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"status": "affected"
},
{
"version": "0",
"lessThan": "3.13",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.10.265",
"lessThanOrEqual": "5.10.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.216",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.183",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.152",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.104",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.45",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.1.9",
"lessThanOrEqual": "7.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-11-06T17:00:47.782346Z",
"id": "CVE-2026-74671",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
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