CVE-2026-74493

Status: UPDATED  |  Advisory ID: CVE-2026-74493

Key Details

Affected Products, Subsystems & Sectors

What to Know

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: addition on 0; use-after-free.

__smc_lgr_terminate.part.0 [smc]

Take the socket reference while conns_lock still protects the tree entry.

The unregister path then cannot drop the last reference until termination

has finished using the socket. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References