CVE-2026-74671 ima: fix out-of-bounds read in xattr_verify()

Q: Is CVE-2026-74671 being exploited?

There is no known exploitation of CVE-2026-74671 in the wild and no public exploit code.

Not scored Published 22 Aug 2026 Updated 22 Aug 2026

A local attacker can trigger an out-of-bounds read in the Linux kernel's IMA subsystem via a truncated extended attribute, potentially leaking memory or causing a crash.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-74671?

CVE-2026-74671 is a memory corruption vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Which versions are affected by CVE-2026-74671?

How do I fix CVE-2026-74671?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-74671 being exploited?