CVE-2026-74493

Technical Description

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

net/smc: fix socket use-after-free during link group termination

__smc_lgr_terminate() drops conns_lock after finding a connection in

lgr->conns_all, but before taking a reference on its socket. The connection

is embedded in the socket, and its registration reference protects it only

while the connection remains in the tree.

A concurrent close can unregister the connection and drop that reference,

freeing the socket before the termination worker reaches sock_hold().

The race is reachable when close overlaps link group termination.

Local stress testing reproduced the use-after-free and KASAN reported:

BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc]

Write of size 4 by task kworker/3:3

Workqueue: events smc_lgr_terminate_work [smc]

__smc_lgr_terminate.part.0 [smc]

The socket was allocated by smc_create(), freed through

slab_free_after_rcu_debug(), and was followed by:

refcount_t: addit

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