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CVE-2026-89494

Estado: RecibidaCrítica (9.8)—

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

ocfs2: validate lengths in dlm_mig_lockres_handler

A node receiving a DLM_MIG_LOCKRES message trusts several fields of the peer-supplied dlm_migratable_lockres without validation. num_locks and lockname_len are bounded only on the sending side, and the message is never checked to actually carry num_locks migratable_lock entries. As a result dlm_process_recovery_data() walks mres->ml[0..num_locks) past the kmalloc(data_len) copy of the message (an out-of-bounds read that ends in a BUG_ON panic), and dlm_init_lockres() copies lockname_len bytes into the fixed 32-byte o2dlm_lockname slab object (a heap out-of-bounds write). Both are reachable by any node in the domain.

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Validate these fields right after dlm_grab(), before anything uses them -- including the not-joined error path, which already prints mres->lockname with the unbounded lockname_len as a %.*s precision. Reject the message unless lockname_len <= DLM_LOCKID_NAME_MAX, num_locks <= DLM_MAX_MIGRATABLE_LOCKS (the bound the sender already asserts), and the payload is large enough to hold the claimed locks. Conforming recovery and migration messages are unaffected.

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.

Red sin autenticación (AV:N/PR:N) permite nodo atacante enviar DLM_MIG_LOCKRES con campos sin validar causando lectura/escritura fuera de límites, panic o corrupción; acceso a datos DLM e impacto en disponibilidad del cluster.

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 TrafficVulnerability ScanningRestrict File and Directory PermissionsPrivileged Account ManagementRemote Data StorageNetwork Segmentation

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-2026-89494",
  "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": "6714d8e86bf443f6f7af50f9d432025649f091f5",
              "lessThan": "4a5798253212093b9ff7d90c6cfbe348bcda1594",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6714d8e86bf443f6f7af50f9d432025649f091f5",
              "lessThan": "dce05b17db862f47ff60614017abe639b2e71cad",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6714d8e86bf443f6f7af50f9d432025649f091f5",
              "lessThan": "0e999d56917f861f97adb961617b1828c9eb4733",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6714d8e86bf443f6f7af50f9d432025649f091f5",
              "lessThan": "77686fa5bba135252d348e2dacf481fc19f60c41",
              "versionType": "git"
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            {
              "status": "affected",
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              "lessThan": "f33041906885f96e190cde54e61ddc69de39e3ee",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6714d8e86bf443f6f7af50f9d432025649f091f5",
              "lessThan": "50c4cc9183e11f83427efbf770f54851f4471c02",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6714d8e86bf443f6f7af50f9d432025649f091f5",
              "lessThan": "a8facb1670b4a0612183198e758d9539ef628ed9",
              "versionType": "git"
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            {
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              "lessThan": "b54e03d9b3697d25f4a0063cf717d459c5e3ad94",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/ocfs2/dlm/dlmrecovery.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "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/ocfs2/dlm/dlmrecovery.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:31.370",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0e999d56917f861f97adb961617b1828c9eb4733",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4a5798253212093b9ff7d90c6cfbe348bcda1594",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/50c4cc9183e11f83427efbf770f54851f4471c02",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/77686fa5bba135252d348e2dacf481fc19f60c41",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a8facb1670b4a0612183198e758d9539ef628ed9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b54e03d9b3697d25f4a0063cf717d459c5e3ad94",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dce05b17db862f47ff60614017abe639b2e71cad",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f33041906885f96e190cde54e61ddc69de39e3ee",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: validate lengths in dlm_mig_lockres_handler\n\nA node receiving a DLM_MIG_LOCKRES message trusts several fields of the\npeer-supplied dlm_migratable_lockres without validation.  num_locks and\nlockname_len are bounded only on the sending side, and the message is\nnever checked to actually carry num_locks migratable_lock entries.  As a\nresult dlm_process_recovery_data() walks mres->ml[0..num_locks) past the\nkmalloc(data_len) copy of the message (an out-of-bounds read that ends in\na BUG_ON panic), and dlm_init_lockres() copies lockname_len bytes into the\nfixed 32-byte o2dlm_lockname slab object (a heap out-of-bounds write). \nBoth are reachable by any node in the domain.\n\nValidate these fields right after dlm_grab(), before anything uses them --\nincluding the not-joined error path, which already prints mres->lockname\nwith the unbounded lockname_len as a %.*s precision.  Reject the message\nunless lockname_len <= DLM_LOCKID_NAME_MAX, num_locks <=\nDLM_MAX_MIGRATABLE_LOCKS (the bound the sender already asserts), and the\npayload is large enough to hold the claimed locks.  Conforming recovery\nand migration messages are unaffected."
    }
  ],
  "lastModified": "2026-09-14T13:19:06.433",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}