# CVE-2026-74692: net/smc: fix TOCTOU race between smc_listen_out() and listener close CVE-2026-74692 is fixed in 17 products on 1 platform, first by DEBIAN-CVE-2026-74692, released August 27, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-74692 - Priority: High - CVSS: 7.5 (Moderate) - EPSS: 0.0049 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Aug 22, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74692 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.81.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.81.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.81.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24197-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24197-1.md) | Nov 7, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.39.1.160000.2.25 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.81.1.150700.17.45.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.39.1.160000.2.26 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.81.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-livepatch-SLE15-SP7-RT_Update_20 sles 15.7 | 1-150700.1.3.1 | [SUSE-SU-2026:4120-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4120-1.md) | Sep 10, 2026 | | Linux | kernel-livepatch-SLE15-SP7_Update_21 sles 15.7 | 1-150700.15.3.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.81.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.81.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.81.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.81.1 | [SUSE-SU-2026:4254-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4254-1.md) | Oct 7, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | linux Debian 12.15 (bookworm) | 6.1.187-1 | [DEBIAN-CVE-2026-74692](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74692.md) | Aug 27, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.105-1 | [DEBIAN-CVE-2026-74692](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74692.md) | Aug 27, 2026 | | Linux | linux Debian 14 | 7.1.9-1 | [DEBIAN-CVE-2026-74692](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74692.md) | Aug 27, 2026 | | Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.107-1~deb12u1 | [DEBIAN-CVE-2026-74692](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74692.md) | Aug 27, 2026 | --- Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.