{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74692", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.926Z", "datePublished": "2026-08-22T15:32:55.873Z", "dateUpdated": "2026-10-16T19:16:09.513Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-25T05:41:37.608Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix TOCTOU race between smc_listen_out() and listener close\n\nsmc_listen_out() reads lsmc->sk.sk_state without the listener lock,\nthen acquires lock_sock_nested() only after the check passes. This\nopens a window where smc_close_active() can transition the listener\nto SMC_CLOSED, call smc_close_cleanup_listen() to drain the accept\nqueue, and release the lock, all between the lockless read and the\ndelayed lock acquisition:\n\n smc_listen_work (smc_hs_wq) smc_close_active()\n ------------------------------- -------------------------\n release_sock(child)\n if (sk_state == SMC_LISTEN) TRUE\n lock_sock(listener)\n sk_state = SMC_CLOSED\n smc_close_cleanup_listen()\n release_sock(listener)\n flush_work(tcp_listen_work)\n lock_sock_nested(listener)\n smc_accept_enqueue(listener, child) /* child enqueued on dead listener */\n\nsmc_close_active() flushes only tcp_listen_work. Work items already\ndispatched onto smc_hs_wq for the CLC handshake continue running\nunguarded. smc_accept_enqueue() takes a sock_hold() on the child that\nis never released, so the child smc_sock, its clcsock, and the\nreference all leak. A remote peer that opens TCP connections while the\nserver calls close() can exhaust kernel memory.\n\nMove lock_sock_nested() to before the sk_state check so that the test\nand the enqueue are atomic under the listener lock." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The bug fires when smc_listen_work() on smc_hs_wq finishes an inbound SMC/TCP handshake queued by smc_tcp_listen_work() for each remote connection to an AF_SMC listener, so any network peer that reaches the listener port drives the full path via SYN and CLC messages.\nAC:L - The attacker controls handshake completions by flooding SMC-capable TCP connections and overlapping them with listener close(), either by timing floods against restarts or locally by running server and client together; smc_close_active() only flushes tcp_listen_work, leaving smc_hs_wq workers racing through the unlocked sk_state check.\nPR:N - SMC performs no authentication; smc_create() and smc_listen() enforce no capabilities, and smc_listen_work() processes the CLC handshake immediately after TCP accept before any credential verification, so an unauthenticated remote peer need only reach the listener port.\nUI:N - Exploitation requires only inbound network connections and kernel handshake/close processing; no end-user action such as opening a file or mounting a filesystem is needed, and listener shutdown during deployments or restarts is routine automated server behavior.\nS:U - The leak accumulates orphaned smc_sock structures and clcsock references within the kernel networking subsystem on the targeted host; it does not cross VM, container, IOMMU, or other security boundaries.\nC:N - The bug is an unreleased sock_hold() leaving child sockets on a closed listener accept queue; objects are never freed prematurely, so there is no out-of-bounds read, use-after-free dereference, or kernel data disclosure to the attacker.\nI:N - Only reference counts are incremented without matching decrements; no memory is written out of bounds, no freed object is reused, and no control-flow or integrity primitive is obtained—only unreclaimable kernel allocations accumulate.\nA:H - Each successful race permanently leaks a child smc_sock, its clcsock, and sock references that smc_close_cleanup_listen() can never drain; a remote peer repeating handshakes during listener close can exhaust kernel memory and cause system-wide denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/smc/af_smc.c" ], "versions": [ { "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9", "lessThan": "53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa", "status": "affected", "versionType": "git" }, { "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9", "lessThan": "feb71634bb1abab3e8fb5cde874b27001cc1282e", "status": "affected", "versionType": "git" }, { "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9", "lessThan": "01865e1ddb126b25ac9eba5cdd7ec49e11183a64", "status": "affected", "versionType": "git" }, { "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9", "lessThan": "00f89433777236ced4771211047fb5d4cd581cea", "status": "affected", "versionType": "git" }, { "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9", "lessThan": "78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67", "status": "affected", "versionType": "git" }, { "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9", "lessThan": "ff5bcd804b5bc5c64736b7d318c20e12ea9506b8", "status": "affected", "versionType": "git" }, { "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9", "lessThan": "185a4caeecabc150106deda1da170b09f2ad803f", "status": "affected", "versionType": "git" }, { "version": "d1d004585b40c212b338fc8a40cbaaf230ea4703", "status": "affected", "versionType": "git" }, { "version": "4.19.299", "lessThan": "4.20", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/smc/af_smc.c" ], "versions": [ { "version": "5.1", "status": "affected" }, { "version": "0", "lessThan": "5.1", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.152", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.104", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.6.152" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.12.104" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.18.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.299" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa" }, { "url": "https://git.kernel.org/stable/c/feb71634bb1abab3e8fb5cde874b27001cc1282e" }, { "url": "https://git.kernel.org/stable/c/01865e1ddb126b25ac9eba5cdd7ec49e11183a64" }, { "url": "https://git.kernel.org/stable/c/00f89433777236ced4771211047fb5d4cd581cea" }, { "url": "https://git.kernel.org/stable/c/78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67" }, { "url": "https://git.kernel.org/stable/c/ff5bcd804b5bc5c64736b7d318c20e12ea9506b8" }, { "url": "https://git.kernel.org/stable/c/185a4caeecabc150106deda1da170b09f2ad803f" } ], "title": "net/smc: fix TOCTOU race between smc_listen_out() and listener close", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74692", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:14:39.954097Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:16:09.513Z" } } ] } }