CVE-2026-74692
net/smc: fix TOCTOU race between smc_listen_out() and listener close
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.
INFO
Published Date :
Aug. 22, 2026, 4:16 p.m.
Last Modified :
Aug. 22, 2026, 4:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-74692
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update the Linux kernel to the latest security version.
- Review kernel change logs for related patches.
- Reboot the system after applying updates.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74692.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74692 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74692
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-74692 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74692 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 22, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9', 'lessThan': '53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa', 'versionType': 'git'}, {'status': 'affected', 'version': 'fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9', 'lessThan': 'feb71634bb1abab3e8fb5cde874b27001cc1282e', 'versionType': 'git'}, {'status': 'affected', 'version': 'fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9', 'lessThan': '01865e1ddb126b25ac9eba5cdd7ec49e11183a64', 'versionType': 'git'}, {'status': 'affected', 'version': 'fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9', 'lessThan': '00f89433777236ced4771211047fb5d4cd581cea', 'versionType': 'git'}, {'status': 'affected', 'version': 'fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9', 'lessThan': '78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67', 'versionType': 'git'}, {'status': 'affected', 'version': 'fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9', 'lessThan': 'ff5bcd804b5bc5c64736b7d318c20e12ea9506b8', 'versionType': 'git'}, {'status': 'affected', 'version': 'fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9', 'lessThan': '185a4caeecabc150106deda1da170b09f2ad803f', 'versionType': 'git'}, {'status': 'affected', 'version': 'd1d004585b40c212b338fc8a40cbaaf230ea4703', 'versionType': 'git'}, {'status': 'affected', 'version': '4.19.299', 'lessThan': '4.20', 'versionType': 'semver'}], 'programFiles': ['net/smc/af_smc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.1'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.1', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.15.216', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.183', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.152', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.104', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.45', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.9', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/smc/af_smc.c'], 'defaultStatus': 'affected'}] Added 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. Added Reference https://git.kernel.org/stable/c/00f89433777236ced4771211047fb5d4cd581cea Added Reference https://git.kernel.org/stable/c/01865e1ddb126b25ac9eba5cdd7ec49e11183a64 Added Reference https://git.kernel.org/stable/c/185a4caeecabc150106deda1da170b09f2ad803f Added Reference https://git.kernel.org/stable/c/53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa Added Reference https://git.kernel.org/stable/c/78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67 Added Reference https://git.kernel.org/stable/c/feb71634bb1abab3e8fb5cde874b27001cc1282e Added Reference https://git.kernel.org/stable/c/ff5bcd804b5bc5c64736b7d318c20e12ea9506b8