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CVE-2026-93786

Estado: RecibidaAlta (8.1)—

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

ksmbd: preserve VFS inherited POSIX ACL mask

The VFS initializes a child's POSIX ACL from the parent's default ACL and the requested creation mode. Do not mutate the parent ACL or overwrite the child's VFS-computed access and default ACLs afterwards.

This preserves restrictive ACL_MASK entries and prevents SMB object creation from widening effective permissions.

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.

Vulnerable SMB service en kernel Linux (AV:N, PR:L) permite escalada de privilegios al manipular ACLs POSIX. Impacto restringido a confidencialidad e integridad sin afectar disponibilidad.

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

User Account ManagementPrivileged Account ManagementUpdate SoftwareVulnerability ScanningThreat Intelligence ProgramRestrict File and Directory Permissions

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-2026-93786",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.1,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "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": "f44158485826c076335d6860d35872271a83791d",
              "lessThan": "4a19bb1c45667f5a5f6eff9cf6648e0f692d046f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "lessThan": "591acf171644de590cda245fd8595b473a1beb70",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "lessThan": "0093909becbda22b62b39b654dbc607faed59cd0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "lessThan": "e148e567a9252643baa125cb65d7ae9c2c6cf68a",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/smb/server/vfs.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.15",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/smb/server/vfs.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-24T17:17:11.243",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0093909becbda22b62b39b654dbc607faed59cd0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4a19bb1c45667f5a5f6eff9cf6648e0f692d046f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/591acf171644de590cda245fd8595b473a1beb70",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e148e567a9252643baa125cb65d7ae9c2c6cf68a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: preserve VFS inherited POSIX ACL mask\n\nThe VFS initializes a child's POSIX ACL from the parent's default ACL and\nthe requested creation mode. Do not mutate the parent ACL or overwrite the\nchild's VFS-computed access and default ACLs afterwards.\n\nThis preserves restrictive ACL_MASK entries and prevents SMB object creation\nfrom widening effective permissions."
    }
  ],
  "lastModified": "2026-10-03T11:17:48.163",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}