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CVE-2026-89658

Estado: RecibidaCrítica (9.8)—

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

NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup

nfs40_clean_admin_revoked() takes a stateid reference under clp->cl_lock, drops nn->client_lock, and calls nfsd4_drop_revoked_stid(), which dereferences the stateid's client through s->sc_client->cl_lock. The stateid reference does not pin the client, so a teardown racing the dropped lock can free the client while nfsd4_drop_revoked_stid() is still using it.

This cleanup runs from the laundromat, so a periodic sweep can race force_expire_client() driven by a write to the clients/<id>/ctl file.

Leer descripción completaMostrar menos

Skip a client that is already expiring and otherwise pin it with cl_rpc_users under client_lock before dropping the lock, matching nfsd4_revoke_states().

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.

Vulnerabilidad remota en NFSD (AV:N, PR:N, UI:N) que causa use-after-free al limpiar estados revocados en NFSv4.0. El acceso remoto no autenticado permite que un atacante provoque condiciones de carrera, resultando en escalada de privilegios (acceso al cl_lock del kernel) o denegación de servicio (c

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

Filter Network TrafficApplication Isolation and SandboxingExploit ProtectionUpdate SoftwareVulnerability ScanningThreat Intelligence Program

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)

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{
  "id": "CVE-2026-89658",
  "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": "d688d8585e6bea5e4e37f7497feea93b6b0a469c",
              "lessThan": "0ae0d2b5c5a1b39c0b3c15d96b32a5b0c583d519",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d688d8585e6bea5e4e37f7497feea93b6b0a469c",
              "lessThan": "b413ec5b23e3445dc9c4f273116078e2d4747626",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d688d8585e6bea5e4e37f7497feea93b6b0a469c",
              "lessThan": "81cf7f1413862f87b078920c838460a6a88aa030",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d688d8585e6bea5e4e37f7497feea93b6b0a469c",
              "lessThan": "7b4f8a1586c42d3afc3c0ac779af2db7ab1a5c55",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.9",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/nfsd/nfs4state.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:52.063",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0ae0d2b5c5a1b39c0b3c15d96b32a5b0c583d519",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7b4f8a1586c42d3afc3c0ac779af2db7ab1a5c55",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/81cf7f1413862f87b078920c838460a6a88aa030",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b413ec5b23e3445dc9c4f273116078e2d4747626",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup\n\nnfs40_clean_admin_revoked() takes a stateid reference under\nclp->cl_lock, drops nn->client_lock, and calls\nnfsd4_drop_revoked_stid(), which dereferences the stateid's client\nthrough s->sc_client->cl_lock.  The stateid reference does not pin the\nclient, so a teardown racing the dropped lock can free the client\nwhile nfsd4_drop_revoked_stid() is still using it.\n\nThis cleanup runs from the laundromat, so a periodic sweep can race\nforce_expire_client() driven by a write to the clients/<id>/ctl file.\n\nSkip a client that is already expiring and otherwise pin it with\ncl_rpc_users under client_lock before dropping the lock, matching\nnfsd4_revoke_states()."
    }
  ],
  "lastModified": "2026-09-13T07:17:31.400",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}