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CVE-2026-74493

Estado: RecibidaCrítica (9.8)—

In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix socket use-after-free during link group termination

__smc_lgr_terminate() drops conns_lock after finding a connection in lgr->conns_all, but before taking a reference on its socket. The connection is embedded in the socket, and its registration reference protects it only while the connection remains in the tree.

A concurrent close can unregister the connection and drop that reference, freeing the socket before the termination worker reaches sock_hold().

The race is reachable when close overlaps link group termination. Local stress testing reproduced the use-after-free and KASAN reported:

Leer descripción completaMostrar menos

The socket was allocated by smc_create(), freed through slab_free_after_rcu_debug(), and was followed by:

Take the socket reference while conns_lock still protects the tree entry. The unregister path then cannot drop the last reference until termination has finished using the socket.

Detalles técnicos trazas, registros y código del informe original
  BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc]
  Write of size 4 by task kworker/3:3
  Workqueue: events smc_lgr_terminate_work [smc]
  __smc_lgr_terminate.part.0 [smc]

  refcount_t: addition on 0; use-after-free.
  __smc_lgr_terminate.part.0 [smc]

CVSS

Probabilidad de explotación (EPSS)

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.

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkFilter Network TrafficApplication Isolation and Sandboxing

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-74493",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
              "lessThan": "ff44f2df57fb5560bdc75eb977867643e764a262",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
              "lessThan": "9fb17c95b8f0683570fca1fb2792264147af937a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
              "lessThan": "bea8dc14de2d56aca749d368563e6888217710a5",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "5a42f162b857019a4c10ff687dc3bcdf51831865",
              "versionType": "git"
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            {
              "status": "affected",
              "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
              "lessThan": "281c103a8eaed59001ce952f231df1b07674215a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "69318b5215f2dc32c345a3d65b98b4b1bf29c007",
              "lessThan": "f807a63d0d95680c34f677700da9148a07d7c78f",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "f0541a775d04c88e90ba448e35ce0d743512822a",
              "versionType": "git"
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            {
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              "lessThan": "f621d6ebeebb6374342571e4ddf45fdbc420f6cd",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/smc/smc_core.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.5"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.5",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/smc/smc_core.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T13:17:54.240",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/281c103a8eaed59001ce952f231df1b07674215a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5a42f162b857019a4c10ff687dc3bcdf51831865",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9fb17c95b8f0683570fca1fb2792264147af937a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bea8dc14de2d56aca749d368563e6888217710a5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f0541a775d04c88e90ba448e35ce0d743512822a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f621d6ebeebb6374342571e4ddf45fdbc420f6cd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f807a63d0d95680c34f677700da9148a07d7c78f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ff44f2df57fb5560bdc75eb977867643e764a262",
      "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 socket use-after-free during link group termination\n\n__smc_lgr_terminate() drops conns_lock after finding a connection in\nlgr->conns_all, but before taking a reference on its socket. The connection\nis embedded in the socket, and its registration reference protects it only\nwhile the connection remains in the tree.\n\nA concurrent close can unregister the connection and drop that reference,\nfreeing the socket before the termination worker reaches sock_hold().\n\nThe race is reachable when close overlaps link group termination.\nLocal stress testing reproduced the use-after-free and KASAN reported:\n\n  BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc]\n  Write of size 4 by task kworker/3:3\n  Workqueue: events smc_lgr_terminate_work [smc]\n  __smc_lgr_terminate.part.0 [smc]\n\nThe socket was allocated by smc_create(), freed through\nslab_free_after_rcu_debug(), and was followed by:\n\n  refcount_t: addition on 0; use-after-free.\n  __smc_lgr_terminate.part.0 [smc]\n\nTake the socket reference while conns_lock still protects the tree entry.\nThe unregister path then cannot drop the last reference until termination\nhas finished using the socket."
    }
  ],
  "lastModified": "2026-08-19T17:21:06.470",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}