CVE-2026-74671

Technical 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 HM

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References