CVE-2026-74692net/smc: fix TOCTOU race between smc_listen_out() and listener close
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 before 53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa; from fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 before feb71634bb1abab3e8fb5cde874b27001cc1282e; from fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 before 01865e1ddb126b25ac9eba5cdd7ec49e11183a64; from fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 before 00f89433777236ced4771211047fb5d4cd581cea; from fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 before 78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67; from fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 before ff5bcd804b5bc5c64736b7d318c20e12ea9506b8; from fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 before 185a4caeecabc150106deda1da170b09f2ad803f; d1d004585b40c212b338fc8a40cbaaf230ea4703; and 1 more ranges | CNA record |
References
- https://git.kernel.org/stable/c/53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa
- https://git.kernel.org/stable/c/feb71634bb1abab3e8fb5cde874b27001cc1282e
- https://git.kernel.org/stable/c/01865e1ddb126b25ac9eba5cdd7ec49e11183a64
- https://git.kernel.org/stable/c/00f89433777236ced4771211047fb5d4cd581cea
- https://git.kernel.org/stable/c/78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67
- https://git.kernel.org/stable/c/ff5bcd804b5bc5c64736b7d318c20e12ea9506b8
- https://git.kernel.org/stable/c/185a4caeecabc150106deda1da170b09f2ad803f
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.