CVE-2026-68147

Estado: RecibidaAlta (7.8)—

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

fscrypt: Avoid dynamic allocation in fscrypt_get_devices()

When a blk_crypto_key starts being used or is evicted, fs/crypto/ calls fscrypt_get_devices() to get the filesystem's list of block devices, then iterates over them and calls blk_crypto_config_supported(), blk_crypto_start_using_key(), or blk_crypto_evict_key() on each one.

Currently, the block device pointers are placed in a dynamically allocated array. This dynamic allocation is problematic because:

For now, let's fix this in the straightforward and easily-backportable way by switching to an on-stack array.

Leer descripción completaMostrar menos

Currently the fscrypt multi-device functionality is used only by f2fs, which has a hardcoded limit of 8 block devices. An on-stack array works fine for that.

(Of course, this solution won't scale up to large number of block devices. For that we'd need a different solution, like moving the block device iteration into the filesystem. Or in the case of btrfs, which will only support blk-crypto-fallback, we should make it just call blk-crypto-fallback directly, so the block devices won't be needed.)

Detalles técnicos trazas, registros y código del informe original

- It can fail, especially at the fscrypt_destroy_inline_crypt_key() call
  site when it's invoked for inode eviction under direct reclaim.

- fscrypt_destroy_inline_crypt_key() doesn't handle the failure.  It
  just zeroizes and frees the blk_crypto_key without calling
  blk_crypto_evict_key().  That causes a use-after-free.

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: 0.17%
Percentil entre todas las CVEs puntuadas: 6
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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1499.004 Application or System Exploitationimpact70 %
Impacto secundarioT1005 Data from Local Systemcollection65 %

Vulnerabilidad local (AV:L/PR:L) en kernel Linux que causa use-after-free en la gestión de claves criptográficas, permitiendo escalada de privilegios y potencial lectura de datos o DoS mediante manipulación de la memoria del kernel.

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-2026-68147",
  "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"
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        "impactScore": 5.9,
        "exploitabilityScore": 1.8
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  "published": "2026-08-10T13:20:00.597",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfscrypt: Avoid dynamic allocation in fscrypt_get_devices()\n\nWhen a blk_crypto_key starts being used or is evicted, fs/crypto/ calls\nfscrypt_get_devices() to get the filesystem's list of block devices,\nthen iterates over them and calls blk_crypto_config_supported(),\nblk_crypto_start_using_key(), or blk_crypto_evict_key() on each one.\n\nCurrently, the block device pointers are placed in a dynamically\nallocated array.  This dynamic allocation is problematic because:\n\n- It can fail, especially at the fscrypt_destroy_inline_crypt_key() call\n  site when it's invoked for inode eviction under direct reclaim.\n\n- fscrypt_destroy_inline_crypt_key() doesn't handle the failure.  It\n  just zeroizes and frees the blk_crypto_key without calling\n  blk_crypto_evict_key().  That causes a use-after-free.\n\nFor now, let's fix this in the straightforward and easily-backportable\nway by switching to an on-stack array.  Currently the fscrypt\nmulti-device functionality is used only by f2fs, which has a hardcoded\nlimit of 8 block devices.  An on-stack array works fine for that.\n\n(Of course, this solution won't scale up to large number of block\ndevices.  For that we'd need a different solution, like moving the block\ndevice iteration into the filesystem.  Or in the case of btrfs, which\nwill only support blk-crypto-fallback, we should make it just call\nblk-crypto-fallback directly, so the block devices won't be needed.)"
    }
  ],
  "lastModified": "2026-08-19T17:20:31.923",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}