CVE-2025-68809

Estado: AplazadaCrítica (9.1)—

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

ksmbd: vfs: fix race on m_flags in vfs_cache

ksmbd maintains delete-on-close and pending-delete state in ksmbd_inode->m_flags. In vfs_cache.c this field is accessed under inconsistent locking: some paths read and modify m_flags under ci->m_lock while others do so without taking the lock at all.

Examples:

This creates a potential data race on m_flags when multiple threads open, close and delete the same file concurrently. In the worst case delete-on-close and pending-delete bits can be lost or observed in an inconsistent state, leading to confusing delete semantics (files that stay on disk after delete-on-close, or files that disappear while still in use).

Leer descripción completaMostrar menos

Fix it by:

This unifies the locking around m_flags and removes the data race while preserving the existing delete-on-close behaviour.

Detalles técnicos trazas, registros y código del informe original

 - ksmbd_query_inode_status() and __ksmbd_inode_close() use
   ci->m_lock when checking or updating m_flags.
 - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),
   ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close()
   used to read and modify m_flags without ci->m_lock.

 - Making ksmbd_query_inode_status() look at m_flags under ci->m_lock
   after dropping inode_hash_lock.
 - Adding ci->m_lock protection to all helpers that read or modify
   m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),
   ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).
 - Keeping the existing ci->m_lock protection in __ksmbd_inode_close(),
   and moving the actual unlink/xattr removal outside the lock.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Puntuación base: 9.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.52%
Percentil entre todas las CVEs puntuadas: 42
Fecha de la puntuación: 5/10/2026

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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application Isolation and Sandboxing

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-2025-68809",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.1,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 5.2,
        "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": "f44158485826c076335d6860d35872271a83791d",
              "lessThan": "5adad9727a815c26013b0d41cfee92ffa7d4037c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "lessThan": "ccc78781041589ea383e61d5d7a1e9a31b210b93",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "lessThan": "ee63729760f5b61a66f345c54dc4c7514e62383d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "lessThan": "991f8a79db99b14c48d20d2052c82d65b9186cad",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/smb/server/vfs_cache.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": "6.6.120",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.64",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/smb/server/vfs_cache.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-01-13T16:16:03.080",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/5adad9727a815c26013b0d41cfee92ffa7d4037c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/991f8a79db99b14c48d20d2052c82d65b9186cad",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ccc78781041589ea383e61d5d7a1e9a31b210b93",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ee63729760f5b61a66f345c54dc4c7514e62383d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: vfs: fix race on m_flags in vfs_cache\n\nksmbd maintains delete-on-close and pending-delete state in\nksmbd_inode->m_flags. In vfs_cache.c this field is accessed under\ninconsistent locking: some paths read and modify m_flags under\nci->m_lock while others do so without taking the lock at all.\n\nExamples:\n\n - ksmbd_query_inode_status() and __ksmbd_inode_close() use\n   ci->m_lock when checking or updating m_flags.\n - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),\n   ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close()\n   used to read and modify m_flags without ci->m_lock.\n\nThis creates a potential data race on m_flags when multiple threads\nopen, close and delete the same file concurrently. In the worst case\ndelete-on-close and pending-delete bits can be lost or observed in an\ninconsistent state, leading to confusing delete semantics (files that\nstay on disk after delete-on-close, or files that disappear while still\nin use).\n\nFix it by:\n\n - Making ksmbd_query_inode_status() look at m_flags under ci->m_lock\n   after dropping inode_hash_lock.\n - Adding ci->m_lock protection to all helpers that read or modify\n   m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),\n   ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).\n - Keeping the existing ci->m_lock protection in __ksmbd_inode_close(),\n   and moving the actual unlink/xattr removal outside the lock.\n\nThis unifies the locking around m_flags and removes the data race while\npreserving the existing delete-on-close behaviour."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nksmbd: vfs: corregir condición de carrera en m_flags en vfs_cache\n\nksmbd mantiene el estado de eliminación al cerrar y eliminación pendiente en ksmbd_inode-&gt;m_flags. En vfs_cache.c, este campo es accedido bajo un bloqueo inconsistente: algunas rutas leen y modifican m_flags bajo ci-&gt;m_lock mientras que otras lo hacen sin tomar el bloqueo en absoluto.\n\nEjemplos:\n\n - ksmbd_query_inode_status() y __ksmbd_inode_close() usan ci-&gt;m_lock al verificar o actualizar m_flags.\n - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete() y ksmbd_fd_set_delete_on_close() solían leer y modificar m_flags sin ci-&gt;m_lock.\n\nEsto crea una potencial condición de carrera de datos en m_flags cuando múltiples hilos abren, cierran y eliminan el mismo archivo concurrentemente. En el peor de los casos, los bits de eliminación al cerrar y eliminación pendiente pueden perderse u observarse en un estado inconsistente, lo que lleva a semánticas de eliminación confusas (archivos que permanecen en el disco después de la eliminación al cerrar, o archivos que desaparecen mientras aún están en uso).\n\nSolucionarlo mediante:\n\n - Haciendo que ksmbd_query_inode_status() examine m_flags bajo ci-&gt;m_lock después de liberar inode_hash_lock.\n - Añadiendo protección ci-&gt;m_lock a todas las funciones auxiliares que leen o modifican m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).\n - Manteniendo la protección ci-&gt;m_lock existente en __ksmbd_inode_close(), y moviendo la eliminación real de unlink/xattr fuera del bloqueo.\n\nEsto unifica el bloqueo alrededor de m_flags y elimina la condición de carrera de datos mientras se preserva el comportamiento existente de eliminación al cerrar."
    }
  ],
  "lastModified": "2026-07-30T06:24:46.520",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}