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CVE-2026-89676

Estado: RecibidaCrítica (9.8)—

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

nfsd: fix stale s2s_cp_stateids IDR entry for async COPY

For an async COPY, nfsd4_copy() called nfs4_init_copy_state() before dup_copy_fields(), so the s2s_cp_stateids IDR was pointed at &u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is reused by the next request. dup_copy_fields() copies only the value into async_copy, so the IDR slot dangled at the transient buffer for the whole background copy. Any IDR walker then dereferences reused request memory: the laundromat reads cs_type from it and, if the bytes look like an expired NFS4_COPYNOTIFY_STID, follows into refcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has the same exposure via idr_find().

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Duplicate the fields first, then register the stateid on the stable async_copy. result->cb_stateid is unchanged.

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.

Vector CVSS AV:N/AC:L/PR:N/UI:N indica explotación remota sin privilegios (T1190). La corrupción de memoria (IDR dangling) causa DoS (laundromat crash) e impacta escalada de privilegios (refcount_dec/kfree() en garbage). Kernel Linux vulnerable.

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-2026-89676",
  "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": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "lessThan": "7aa34ea78f74e6ef60c8112635a87fc43d57f6c9",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "lessThan": "9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "lessThan": "14b978e8d05ce018d0afbeb6611833ef91713a02",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3",
              "lessThan": "d0beaee498e11880e72826026db0e9c9890fc114",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/nfsd/nfs4proc.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.20"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.20",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "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/nfs4proc.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:54.273",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/14b978e8d05ce018d0afbeb6611833ef91713a02",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7aa34ea78f74e6ef60c8112635a87fc43d57f6c9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d0beaee498e11880e72826026db0e9c9890fc114",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix stale s2s_cp_stateids IDR entry for async COPY\n\nFor an async COPY, nfsd4_copy() called nfs4_init_copy_state() before\ndup_copy_fields(), so the s2s_cp_stateids IDR was pointed at\n&u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is\nreused by the next request. dup_copy_fields() copies only the value into\nasync_copy, so the IDR slot dangled at the transient buffer for the whole\nbackground copy. Any IDR walker then dereferences reused request memory:\nthe laundromat reads cs_type from it and, if the bytes look like an\nexpired NFS4_COPYNOTIFY_STID, follows into\nrefcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has\nthe same exposure via idr_find().\n\nDuplicate the fields first, then register the stateid on the stable\nasync_copy. result->cb_stateid is unchanged."
    }
  ],
  "lastModified": "2026-09-21T14:17:25.073",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}