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

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Puntuación base: 8.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.34%
Percentil entre todas las CVEs puntuadas: 25
Fecha de la puntuación: 6/10/2026

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.

ExplotaciónT1210 Exploitation of Remote Serviceslateral movement45 %
Impacto principalT1548 Abuse Elevation Control Mechanismprivilege escalation65 %
Impacto secundarioT1548.005 Temporary Elevated Cloud Accessprivilege escalation60 %

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 Management Privileged Account Management Update Software Vulnerability Scanning Threat Intelligence Program Restrict 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 Kernel^AI

Referencias

JSON original (NVD)

Mostrar

{
  "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"
}