CVE-2026-74692
Received
Received - Intake
Race Condition in Linux Kernel SMC Module
Vulnerability report for CVE-2026-74692, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-08-22
Last updated on: 2026-08-22
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix TOCTOU race between smc_listen_out() and listener close
smc_listen_out() reads lsmc->sk.sk_state without the listener lock,
then acquires lock_sock_nested() only after the check passes. This
opens a window where smc_close_active() can transition the listener
to SMC_CLOSED, call smc_close_cleanup_listen() to drain the accept
queue, and release the lock, all between the lockless read and the
delayed lock acquisition:
smc_listen_work (smc_hs_wq) smc_close_active()
------------------------------- -------------------------
release_sock(child)
if (sk_state == SMC_LISTEN) TRUE
lock_sock(listener)
sk_state = SMC_CLOSED
smc_close_cleanup_listen()
release_sock(listener)
flush_work(tcp_listen_work)
lock_sock_nested(listener)
smc_accept_enqueue(listener, child) /* child enqueued on dead listener */
smc_close_active() flushes only tcp_listen_work. Work items already
dispatched onto smc_hs_wq for the CLC handshake continue running
unguarded. smc_accept_enqueue() takes a sock_hold() on the child that
is never released, so the child smc_sock, its clcsock, and the
reference all leak. A remote peer that opens TCP connections while the
server calls close() can exhaust kernel memory.
Move lock_sock_nested() to before the sk_state check so that the test
and the enqueue are atomic under the listener lock.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
