FKIE_CVE-2026-74692

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-10-14 13:10
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/00f89433777236ced4771211047fb5d4cd581cea
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/01865e1ddb126b25ac9eba5cdd7ec49e11183a64
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/185a4caeecabc150106deda1da170b09f2ad803f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/feb71634bb1abab3e8fb5cde874b27001cc1282e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ff5bcd804b5bc5c64736b7d318c20e12ea9506b8
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/smc/af_smc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa",
              "status": "affected",
              "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9",
              "versionType": "git"
            },
            {
              "lessThan": "feb71634bb1abab3e8fb5cde874b27001cc1282e",
              "status": "affected",
              "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9",
              "versionType": "git"
            },
            {
              "lessThan": "01865e1ddb126b25ac9eba5cdd7ec49e11183a64",
              "status": "affected",
              "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9",
              "versionType": "git"
            },
            {
              "lessThan": "00f89433777236ced4771211047fb5d4cd581cea",
              "status": "affected",
              "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9",
              "versionType": "git"
            },
            {
              "lessThan": "78e5ebcd1c10ed7c8bda0a99e0abd5b62da86d67",
              "status": "affected",
              "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9",
              "versionType": "git"
            },
            {
              "lessThan": "ff5bcd804b5bc5c64736b7d318c20e12ea9506b8",
              "status": "affected",
              "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9",
              "versionType": "git"
            },
            {
              "lessThan": "185a4caeecabc150106deda1da170b09f2ad803f",
              "status": "affected",
              "version": "fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d1d004585b40c212b338fc8a40cbaaf230ea4703",
              "versionType": "git"
            },
            {
              "lessThan": "4.20",
              "status": "affected",
              "version": "4.19.299",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/smc/af_smc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.1"
            },
            {
              "lessThan": "5.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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-\u003esk.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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet/smc: corrige la condici\u00f3n de carrera TOCTOU entre smc_listen_out() y el cierre del oyente\n\nsmc_listen_out() lee lsmc -\u003e sk.sk_state sin el bloqueo del oyente, luego adquiere lock_sock_nested() solo despu\u00e9s de que la verificaci\u00f3n pasa. Esto abre una ventana donde smc_close_active() puede hacer la transici\u00f3n del oyente a SMC_CLOSED, llamar a smc_close_cleanup_listen() para vaciar la cola de aceptaci\u00f3n y liberar el bloqueo, todo entre la lectura sin bloqueo y la adquisici\u00f3n de bloqueo retrasada:\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) /* hijo encolado en oyente inactivo */\n\nsmc_close_active() vac\u00eda solo tcp_listen_work. Los elementos de trabajo ya despachados a smc_hs_wq para el handshake CLC contin\u00faan ejecut\u00e1ndose sin protecci\u00f3n. smc_accept_enqueue() toma un sock_hold() en el hijo que nunca se libera, por lo que el smc_sock hijo, su clcsock y la referencia se filtran. Un par remoto que abre conexiones TCP mientras el servidor llama a close() puede agotar la memoria del kernel.\n\nMover lock_sock_nested() a antes de la verificaci\u00f3n de sk_state para que la prueba y la encolaci\u00f3n sean at\u00f3micas bajo el bloqueo del oyente."
    }
  ],
  "id": "CVE-2026-74692",
  "lastModified": "2026-10-14T13:10:00.187",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:43.667",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/00f89433777236ced4771211047fb5d4cd581cea"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/01865e1ddb126b25ac9eba5cdd7ec49e11183a64"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/185a4caeecabc150106deda1da170b09f2ad803f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/53c7938d8bcfde3296ec1a347ba2a9393c1fdcfa"
    },
    {
      "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"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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