CVE-2026-74692
Estado: RecibidaAlta (7.5)—
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_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.
Leer descripción completaMostrar menos
Move lock_sock_nested() to before the sk_state check so that the test and the enqueue are atomic under the listener lock.
Detalles técnicos trazas, registros y código del informe original
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 */CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 7.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.70%
- Percentil entre todas las CVEs puntuadas: 52
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1190Exploit Public-Facing Applicationinitial access75 % - Impacto principal
T1499.004Application or System Exploitationimpact80 % - Impacto secundario
T1499Endpoint Denial of Serviceimpact70 %
Vulnerabilidad de race condition en red (AV:N, PR:N, UI:N) que permite a un atacante remoto agotar memoria del kernel mediante conexiones TCP concurrentes, causando denegación de servicio de recursos (A:H).
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/00f89433777236ced4771211047fb5d4cd581cea
- https://git.kernel.org/stable/c/01865e1ddb126b25ac9eba5cdd7ec49e11183a64
- https://git.kernel.org/stable/c/185a4caeecabc150106deda1da170b09f2ad803f
- https://git.kernel.org/stable/c/53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa
- https://git.kernel.org/stable/c/78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67
- https://git.kernel.org/stable/c/feb71634bb1abab3e8fb5cde874b27001cc1282e
- https://git.kernel.org/stable/c/ff5bcd804b5bc5c64736b7d318c20e12ea9506b8
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-74692",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.5,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
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],
"programFiles": [
"net/smc/af_smc.c"
],
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},
{
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"vendor": "Linux",
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},
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"version": "0",
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{
"status": "unaffected",
"version": "5.15.216",
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},
{
"status": "unaffected",
"version": "6.1.183",
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},
{
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/smc/af_smc.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-22T16:16:43.667",
"references": [
{
"url": "https://git.kernel.org/stable/c/00f89433777236ced4771211047fb5d4cd581cea",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/feb71634bb1abab3e8fb5cde874b27001cc1282e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ff5bcd804b5bc5c64736b7d318c20e12ea9506b8",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"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."
}
],
"lastModified": "2026-08-25T06:18:52.767",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}