CVE-2026-72381

Estado: RecibidaCrítica (9.8)—

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

ksmbd: fix use-after-free of fp->owner.name in durable handle owner check

Two concurrent SMB2 durable reconnects (DH2C/DHnC) on the same persistent_id race the fp->owner.name compare-read in ksmbd_vfs_compare_durable_owner() against the kfree() in ksmbd_reopen_durable_fd()'s reopen-success path. fp->owner.name is a standalone kstrdup() buffer whose lifetime is independent of the fp refcount, and the two sites share no lock: the compare reads the buffer while the reopen frees it, so the strcmp() can dereference freed memory.

Commit 7ce4fc40018d ("ksmbd: fix durable reconnect double-bind race in ksmbd_reopen_durable_fd") made the fp->conn claim atomic under global_ft.lock (closing the owner.name double-free and the ksmbd_file write-UAF), but the compare-read versus reopen-free pair was left unserialized.

Leer descripción completaMostrar menos

Serialize both sides of the race with fp->f_lock. The global durable file-table lock still protects the durable reconnect claim, but fp->owner.name is per-open state and does not need to block unrelated durable table lookups or reconnects. The teardown is left at its existing location after the reopen-success point so that an __open_id() rollback still retains owner.name for a later legitimate reconnect to verify.

Detalles técnicos trazas, registros y código del informe original

  BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80
  Read of size 1 by task kworker
    strcmp
    ksmbd_vfs_compare_durable_owner
    smb2_check_durable_oplock
    smb2_open
  Freed by task kworker:
    kfree
    ksmbd_reopen_durable_fd
    smb2_open
  Allocated by task kworker:
    kstrdup
    session_fd_check
    smb2_session_logoff
  The buggy address belongs to the cache kmalloc-8

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 9.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.65%
Percentil entre todas las CVEs puntuadas: 50
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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access75 %

CVE crítica en kernel Linux (AV:N, sin autenticación). Use-after-free permite ejecución remota de código con acceso de red no autenticado (T1190), derivando en escalada de privilegios (root/kernel) y lectura de memoria del sistema (T1068, T1005).

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

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-2026-72381",
  "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
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          "programFiles": [
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          "programFiles": [
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  "published": "2026-08-15T06:22:11.587",
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      "url": "https://git.kernel.org/stable/c/38637163501fd9e2f684b8cd275d0db5d79f37c6",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free of fp->owner.name in durable handle owner check\n\nTwo concurrent SMB2 durable reconnects (DH2C/DHnC) on the same\npersistent_id race the fp->owner.name compare-read in\nksmbd_vfs_compare_durable_owner() against the kfree() in\nksmbd_reopen_durable_fd()'s reopen-success path. fp->owner.name is a\nstandalone kstrdup() buffer whose lifetime is independent of the fp\nrefcount, and the two sites share no lock: the compare reads the buffer\nwhile the reopen frees it, so the strcmp() can dereference freed memory.\n\nCommit 7ce4fc40018d (\"ksmbd: fix durable reconnect double-bind race in\nksmbd_reopen_durable_fd\") made the fp->conn claim atomic under\nglobal_ft.lock (closing the owner.name double-free and the ksmbd_file\nwrite-UAF), but the compare-read versus reopen-free pair was left\nunserialized.\n\n  BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80\n  Read of size 1 by task kworker\n    strcmp\n    ksmbd_vfs_compare_durable_owner\n    smb2_check_durable_oplock\n    smb2_open\n  Freed by task kworker:\n    kfree\n    ksmbd_reopen_durable_fd\n    smb2_open\n  Allocated by task kworker:\n    kstrdup\n    session_fd_check\n    smb2_session_logoff\n  The buggy address belongs to the cache kmalloc-8\n\nSerialize both sides of the race with fp->f_lock.  The global durable\nfile-table lock still protects the durable reconnect claim, but\nfp->owner.name is per-open state and does not need to block unrelated\ndurable table lookups or reconnects.  The teardown is left at its\nexisting location after the reopen-success point so that an __open_id()\nrollback still retains owner.name for a later legitimate reconnect to\nverify."
    }
  ],
  "lastModified": "2026-08-17T06:18:42.503",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}