CVE-2026-74692

CVE CVE-2026-74692EUVD EUVD-2026-64379Published 2026-08-22T15:32:55.000ZLast changed 2026-08-25T05:41:37.000ZCVSS 7.5

What the advisory describes

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.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 <00f89433777236ced4771211047fb5d4cd581cea; fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 <ff5bcd804b5bc5c64736b7d318c20e12ea9506b8; 4.19.299 <4.20; patch: 6.6.152; patch: 6.18.45; 5.1; patch: 6.12.104; fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 <01865e1ddb126b25ac9eba5cdd7ec49e11183a64; fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 <78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67; patch: 5.15.216; d1d004585b40c212b338fc8a40cbaaf230ea4703; fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 <185a4caeecabc150106deda1da170b09f2ad803f; fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 <53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa; patch: 7.2; fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 <feb71634bb1abab3e8fb5cde874b27001cc1282e; patch: 7.1.9; patch: 0; patch: 6.1.183

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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