CVE-2026-74590

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

fsverity: Fix bpf_get_fsverity_digest() dynptr assumptions

The BPF verifier and the dynptr abstraction ensure that the memory space

referenced by a dynptr remains valid. They do not, however, provide any

guarantee that the contents of the memory are stable. kfuncs are

expected to remain memory-safe even if concurrent modifications occur.

bpf_get_fsverity_digest() didn't follow that: it could crash if

arg->digest_size was concurrently modified.

Fix that by using the known-good value hash_alg->digest_size instead.

Also widen 'dynptr_sz' and 'out_digest_sz' to u64 to match the return

type of __bpf_dynptr_size(). It doesn't appear that it can actually be

more than INT_MAX currently (since __bpf_dynptr_data_rw() excludes

file-based pointers), but the correct type might as well be used.

/// 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