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CVE-2026-89703

Estado: RecibidaCrítica (9.8)—

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

nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations

nfsd4_drop_revoked_stid() handles FREE_STATEID for admin-revoked delegations but does not set SC_STATUS_FREED before releasing cl_lock. revoke_delegation() uses this flag to detect whether FREE_STATEID has already processed the delegation -- without it, the freed delegation is added to cl_revoked via list_add(), producing a use-after-free when cl_revoked is later traversed in __destroy_client().

The SC_STATUS_REVOKED path in nfsd4_free_stateid() (line 7983) already sets SC_STATUS_FREED correctly. Apply the same pattern to the SC_STATUS_ADMIN_REVOKED path in nfsd4_drop_revoked_stid().

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 crítica (CVSS 9.9) en nfsd del kernel Linux sin autenticación (PR:N, UI:N). La use-after-free permite escalada a root o DoS; acceso remoto de red sin privilegios por defecto T1190, aunque el impacto final es T1068 (privilegios root) y potencial T1499.004 (crash/DoS).

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-2026-89703",
  "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": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "lessThan": "d832a0587528853d45481d1faf75d4b5d062adaf",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "lessThan": "1e4795766719ffd74b8cf0f2fde4a1350f8326bf",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "lessThan": "a6d89032e5c6620d5bb44582a72555ce07bf1c2e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a",
              "lessThan": "650d370cfbc66a96dd14d517bd704689b5bda4e5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "967faa26f313a62e7bebc55d5b8122eaee43b929",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6.11.6",
              "lessThan": "6.12",
              "versionType": "semver"
            }
          ],
          "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": "6.12"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.12",
              "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": "2026-09-11T20:19:57.537",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1e4795766719ffd74b8cf0f2fde4a1350f8326bf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/650d370cfbc66a96dd14d517bd704689b5bda4e5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a6d89032e5c6620d5bb44582a72555ce07bf1c2e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d832a0587528853d45481d1faf75d4b5d062adaf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations\n\nnfsd4_drop_revoked_stid() handles FREE_STATEID for admin-revoked\ndelegations but does not set SC_STATUS_FREED before releasing cl_lock.\nrevoke_delegation() uses this flag to detect whether FREE_STATEID has\nalready processed the delegation -- without it, the freed delegation is\nadded to cl_revoked via list_add(), producing a use-after-free when\ncl_revoked is later traversed in __destroy_client().\n\nThe SC_STATUS_REVOKED path in nfsd4_free_stateid() (line 7983) already\nsets SC_STATUS_FREED correctly. Apply the same pattern to the\nSC_STATUS_ADMIN_REVOKED path in nfsd4_drop_revoked_stid()."
    }
  ],
  "lastModified": "2026-09-13T07:17:35.860",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}