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CVE-2026-90199

Estado: RecibidaAlta (7.8)—

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

fs/ntfs3: reject out-of-range evcn in mi_enum_attr()

In mi_enum_attr(), the start/end VCN validation for non-resident attributes is:

When evcn is U64_MAX the "evcn + 1" expression wraps to 0 and any svcn passes the check. For evcn values close to U64_MAX (but not equal to it) the right-hand side is still a meaningless near-wrap upper bound, so a malformed on-disk attribute with svcn == 0 and evcn near U64_MAX can pass mi_enum_attr() unrejected.

VCN (virtual cluster number) is a cluster index, so any valid evcn is bounded by the volume's total cluster count, which ntfs3 holds in sbi->used.bitmap.nbits (set up in ntfs_init_from_boot() before any caller of mi_enum_attr() runs).

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Reject evcn values that fall outside this range.

However, an empty non-resident attribute (no allocated clusters) is legitimately encoded with svcn == 0 and evcn == -1 (U64_MAX), e.g. via attr->nres.evcn = cpu_to_le64((u64)vcn - 1) with vcn == 0. That sentinel must keep passing, so exclude evcn == U64_MAX from the range check. The existing "svcn > evcn + 1" test still tolerates the sentinel ("0 > 0" is false) and continues to require svcn == 0 for it, while the range check rejects every other out-of-range evcn and thereby also defuses the "evcn + 1" wraparound.

svcn does not need its own bound: once evcn < nbits, "svcn > evcn + 1" implies svcn <= nbits.

[almaz.alexandrovich@paragon-software.com: fixed evcn check]

Detalles técnicos trazas, registros y código del informe original
	if (svcn > evcn + 1) goto out;

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 local (AV:L, PR:N, UI:R) en kernel Linux que permite manipular validaciones de atributos NTFS sin privilegios. El desbordamiento de U64_MAX al procesar evcn permite ejecución de código o manipulación de datos del filesystem tras interacción del usuario.

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

Restrict File and Directory PermissionsRemote Data StorageExecution PreventionEncrypt Sensitive InformationApplication Isolation and SandboxingExploit Protection

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-2026-90199",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "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": "013ff63b649475f0ee134e2c8d0c8e65284ede50",
              "lessThan": "0441e34ce098c19185a7b52c5b8b89a8a5b26888",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "013ff63b649475f0ee134e2c8d0c8e65284ede50",
              "lessThan": "7ab69cef49ebdfee288287d62641b24ab1445ecc",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "013ff63b649475f0ee134e2c8d0c8e65284ede50",
              "lessThan": "ce9a619c432b9a4044fee115c5483fbed946c131",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "2b9a0e57bfd365e2096706b19ae34dce3b4a884b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "013ff63b649475f0ee134e2c8d0c8e65284ede50",
              "lessThan": "20fd9f64c0050658f2031e6bd5d552c6f0c8f7e3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a7accf181a4709a6e380360372150cc4a1b6b89a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3dfd727873c3e8da74a2e3907120ff052c5f0bcc",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1d7dd485108d4f633b543c9c14071cc325b68ae5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5.15.209",
              "lessThan": "5.16",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.1.115",
              "lessThan": "6.2",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.5.11",
              "lessThan": "6.6",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "fs/ntfs3/record.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.6",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/ntfs3/record.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-17T17:17:14.790",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0441e34ce098c19185a7b52c5b8b89a8a5b26888",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/20fd9f64c0050658f2031e6bd5d552c6f0c8f7e3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2b9a0e57bfd365e2096706b19ae34dce3b4a884b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7ab69cef49ebdfee288287d62641b24ab1445ecc",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ce9a619c432b9a4044fee115c5483fbed946c131",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: reject out-of-range evcn in mi_enum_attr()\n\nIn mi_enum_attr(), the start/end VCN validation for non-resident\nattributes is:\n\n\tif (svcn > evcn + 1) goto out;\n\nWhen evcn is U64_MAX the \"evcn + 1\" expression wraps to 0 and any svcn\npasses the check. For evcn values close to U64_MAX (but not equal to it)\nthe right-hand side is still a meaningless near-wrap upper bound, so a\nmalformed on-disk attribute with svcn == 0 and evcn near U64_MAX can pass\nmi_enum_attr() unrejected.\n\nVCN (virtual cluster number) is a cluster index, so any valid evcn is\nbounded by the volume's total cluster count, which ntfs3 holds in\nsbi->used.bitmap.nbits (set up in ntfs_init_from_boot() before any caller\nof mi_enum_attr() runs). Reject evcn values that fall outside this range.\n\nHowever, an empty non-resident attribute (no allocated clusters) is\nlegitimately encoded with svcn == 0 and evcn == -1 (U64_MAX), e.g. via\nattr->nres.evcn = cpu_to_le64((u64)vcn - 1) with vcn == 0. That sentinel\nmust keep passing, so exclude evcn == U64_MAX from the range check. The\nexisting \"svcn > evcn + 1\" test still tolerates the sentinel (\"0 > 0\" is\nfalse) and continues to require svcn == 0 for it, while the range check\nrejects every other out-of-range evcn and thereby also defuses the\n\"evcn + 1\" wraparound.\n\nsvcn does not need its own bound: once evcn < nbits, \"svcn > evcn + 1\"\nimplies svcn <= nbits.\n\n[almaz.alexandrovich@paragon-software.com: fixed evcn check]"
    }
  ],
  "lastModified": "2026-09-18T18:17:45.950",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}