CVE-2026-63814

Estado: Pendiente de análisisAlta (7.8)—

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

f2fs: validate ACL entry sizes in f2fs_acl_from_disk()

f2fs_acl_count() only validates the aggregate ACL xattr length. A malformed ACL can still place ACL_USER or ACL_GROUP in a slot that only contains struct f2fs_acl_entry_short bytes, and f2fs_acl_from_disk() then reads entry->e_id before verifying that a full entry fits.

Require a short entry before reading e_tag and e_perm, and require a full entry before reading e_id for ACL_USER and ACL_GROUP. Return -EFSCORRUPTED from these new truncated-entry checks, while keeping the pre-existing -EINVAL paths unchanged.

Detalles técnicos trazas, registros y código del informe original

Validation reproduced this kernel report:
KASAN slab-out-of-bounds in __f2fs_get_acl+0x6fb/0x7e0
RIP: 0033:0x7f4b835ea7aa
The buggy address belongs to the object at ffff888114589960 which belongs
to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of allocated 8-byte
region [ffff888114589960, ffff888114589968)
Read of size 4
Call trace:
  dump_stack_lvl+0x66/0xa0 (?:?)
  print_report+0xce/0x630 (?:?)
  __f2fs_get_acl+0x6fb/0x7e0 (fs/f2fs/acl.c:169)
  srso_alias_return_thunk+0x5/0xfbef5 (?:?)
  __virt_addr_valid+0x224/0x430 (?:?)
  kasan_report+0xe0/0x110 (?:?)
  __f2fs_get_acl+0x5/0x7e0 (fs/f2fs/acl.c:169)
  __get_acl+0x281/0x380 (?:?)
  vfs_get_acl+0x10b/0x190 (?:?)
  do_get_acl+0x2a/0x410 (?:?)
  do_get_acl+0x9/0x410 (?:?)
  do_getxattr+0xe8/0x260 (?:?)
  filename_getxattr+0xd1/0x140 (?:?)
  do_getname+0x2d/0x2d0 (?:?)
  path_getxattrat+0x16c/0x200 (?:?)
  lock_release+0xc8/0x290 (?:?)
  cgroup_update_frozen+0x9d/0x320 (?:?)
  lockdep_hardirqs_on_prepare+0xea/0x1a0 (?:?)
  trace_hardirqs_on+0x1a/0x170 (?:?)
  _raw_spin_unlock_irq+0x28/0x50 (?:?)
  do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)
  entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.13%
Percentil entre todas las CVEs puntuadas: 2
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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation90 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1005 Data from Local Systemcollection60 %

Vulnerabilidad local (AV:L/PR:L) de corrupción de memoria (KASAN slab-out-of-bounds) en ACL de f2fs permite escalada de privilegios; lectura de datos fuera de límites y potencial DoS por corrupción.

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

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

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-2026-63814",
  "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:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "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": "af48b85b8cd3fbb12c9b6759c16db6d69c0b03da",
              "lessThan": "733cd8474e6d763d75ed96f3f2b98a25480cf2b9",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "af48b85b8cd3fbb12c9b6759c16db6d69c0b03da",
              "lessThan": "4e2a96ec7236e248e706850568e0a925fd21b588",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "af48b85b8cd3fbb12c9b6759c16db6d69c0b03da",
              "lessThan": "442ca20c54038e2400cf28aaa944cf1de2c8e65d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "af48b85b8cd3fbb12c9b6759c16db6d69c0b03da",
              "lessThan": "1ddf3fd21c4c652f9cab5552515c04a166662306",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "af48b85b8cd3fbb12c9b6759c16db6d69c0b03da",
              "lessThan": "aba4f94ac1832c7299c33e1b4fe5f87eef6dc8f1",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "af48b85b8cd3fbb12c9b6759c16db6d69c0b03da",
              "lessThan": "ff83de56882cb8466184d322abece2589258ca56",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "af48b85b8cd3fbb12c9b6759c16db6d69c0b03da",
              "lessThan": "5d8a39649947a4e86c8fbc682d7fc0041b8d109a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "af48b85b8cd3fbb12c9b6759c16db6d69c0b03da",
              "lessThan": "c4810ada31e80cbe4011467c4f3b1e93f94134f3",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/f2fs/acl.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.8"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "3.8",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.260",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.211",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.177",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.144",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/f2fs/acl.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-07-19T12:16:54.390",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1ddf3fd21c4c652f9cab5552515c04a166662306",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/442ca20c54038e2400cf28aaa944cf1de2c8e65d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4e2a96ec7236e248e706850568e0a925fd21b588",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5d8a39649947a4e86c8fbc682d7fc0041b8d109a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/733cd8474e6d763d75ed96f3f2b98a25480cf2b9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/aba4f94ac1832c7299c33e1b4fe5f87eef6dc8f1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c4810ada31e80cbe4011467c4f3b1e93f94134f3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ff83de56882cb8466184d322abece2589258ca56",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: validate ACL entry sizes in f2fs_acl_from_disk()\n\nf2fs_acl_count() only validates the aggregate ACL xattr length. A\nmalformed ACL can still place ACL_USER or ACL_GROUP in a slot that only\ncontains struct f2fs_acl_entry_short bytes, and f2fs_acl_from_disk()\nthen reads entry->e_id before verifying that a full entry fits.\n\nRequire a short entry before reading e_tag and e_perm, and require a\nfull entry before reading e_id for ACL_USER and ACL_GROUP. Return\n-EFSCORRUPTED from these new truncated-entry checks, while keeping the\npre-existing -EINVAL paths unchanged.\n\nValidation reproduced this kernel report:\nKASAN slab-out-of-bounds in __f2fs_get_acl+0x6fb/0x7e0\nRIP: 0033:0x7f4b835ea7aa\nThe buggy address belongs to the object at ffff888114589960 which belongs\nto the cache kmalloc-8 of size 8\nThe buggy address is located 0 bytes to the right of allocated 8-byte\nregion [ffff888114589960, ffff888114589968)\nRead of size 4\nCall trace:\n  dump_stack_lvl+0x66/0xa0 (?:?)\n  print_report+0xce/0x630 (?:?)\n  __f2fs_get_acl+0x6fb/0x7e0 (fs/f2fs/acl.c:169)\n  srso_alias_return_thunk+0x5/0xfbef5 (?:?)\n  __virt_addr_valid+0x224/0x430 (?:?)\n  kasan_report+0xe0/0x110 (?:?)\n  __f2fs_get_acl+0x5/0x7e0 (fs/f2fs/acl.c:169)\n  __get_acl+0x281/0x380 (?:?)\n  vfs_get_acl+0x10b/0x190 (?:?)\n  do_get_acl+0x2a/0x410 (?:?)\n  do_get_acl+0x9/0x410 (?:?)\n  do_getxattr+0xe8/0x260 (?:?)\n  filename_getxattr+0xd1/0x140 (?:?)\n  do_getname+0x2d/0x2d0 (?:?)\n  path_getxattrat+0x16c/0x200 (?:?)\n  lock_release+0xc8/0x290 (?:?)\n  cgroup_update_frozen+0x9d/0x320 (?:?)\n  lockdep_hardirqs_on_prepare+0xea/0x1a0 (?:?)\n  trace_hardirqs_on+0x1a/0x170 (?:?)\n  _raw_spin_unlock_irq+0x28/0x50 (?:?)\n  do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)\n  entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)"
    }
  ],
  "lastModified": "2026-08-17T05:17:18.567",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}