CVE-2026-80845

/// Technical description

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

xfrm: avoid lock inversion in nat keepalive work

nat_keepalive_work() walks the state table while xfrm_state_walk()

holds net->xfrm.xfrm_state_lock. Its callback then acquires x->lock,

which conflicts with the delete path taking the same locks in reverse

order via xfrm_state_delete() and __xfrm_state_delete(). This creates

an AB-BA deadlock that is reported by lockdep when a NAT keepalive

worker races with SA deletion.

Fix this by splitting the keepalive walk into two phases. First,

collect the candidate states while the walk holds xfrm_state_lock and

take a reference on each state. Then, after the walk completes, process

each collected state and acquire x->lock without nesting it under

xfrm_state_lock.

/// 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