CVE-2026-31516

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

xfrm: prevent policy_hthresh.work from racing with netns teardown

A XFRM_MSG_NEWSPDINFO request can queue the per-net work item

policy_hthresh.work onto the system workqueue.

The queued callback, xfrm_hash_rebuild(), retrieves the enclosing

struct net via container_of(). If the net namespace is torn down

before that work runs, the associated struct net may already have

been freed, and xfrm_hash_rebuild() may then dereference stale memory.

xfrm_policy_fini() already flushes policy_hash_work during teardown,

but it does not synchronize policy_hthresh.work.

Synchronize policy_hthresh.work in xfrm_policy_fini() as well, so the

queued work cannot outlive the net namespace teardown and access a

freed struct net.