CVE-2022-50668

Estado: AplazadaAlta (7.5)—

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

ext4: fix deadlock due to mbcache entry corruption

When manipulating xattr blocks, we can deadlock infinitely looping inside ext4_xattr_block_set() where we constantly keep finding xattr block for reuse in mbcache but we are unable to reuse it because its reference count is too big. This happens because cache entry for the xattr block is marked as reusable (e_reusable set) although its reference count is too big. When this inconsistency happens, this inconsistent state is kept indefinitely and so ext4_xattr_block_set() keeps retrying indefinitely.

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The inconsistent state is caused by non-atomic update of e_reusable bit. e_reusable is part of a bitfield and e_reusable update can race with update of e_referenced bit in the same bitfield resulting in loss of one of the updates. Fix the problem by using atomic bitops instead.

This bug has been around for many years, but it became *much* easier to hit after commit 65f8b80053a1 ("ext4: fix race when reusing xattr blocks").

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.81%
Percentil entre todas las CVEs puntuadas: 55
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 access60 %
Impacto principalT1499 Endpoint Denial of Serviceimpact55 %

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

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network 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-2022-50668",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "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": "6048c64b26097a0ffbd966866b599f990e674e9b",
              "lessThan": "efaa0ca678f56d47316a08030b2515678cebbc50",
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          ],
          "programFiles": [
            "fs/ext4/xattr.c",
            "fs/mbcache.c",
            "include/linux/mbcache.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.6"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.6",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "4.19.270",
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              "lessThanOrEqual": "4.19.*"
            },
            {
              "status": "unaffected",
              "version": "5.4.229",
              "versionType": "semver",
              "lessThanOrEqual": "5.4.*"
            },
            {
              "status": "unaffected",
              "version": "5.10.163",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.87",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.0.18",
              "versionType": "semver",
              "lessThanOrEqual": "6.0.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.4",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/ext4/xattr.c",
            "fs/mbcache.c",
            "include/linux/mbcache.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-12-09T16:17:18.830",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/127b80cefb941a81255c72f11081123f3a705369",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1be16a0c2f10186df505e28b0cc92d7f3366e2a8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5bc0b2fda4b47c86278f7c6d30c211f425bf51cf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a44e84a9b7764c72896f7241a0ec9ac7e7ef38dd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://git.kernel.org/stable/c/af53065276376750dfac35a7248af18806404c5d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cc1538c693d25e282bed8c54b65c914a04023a78",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/efaa0ca678f56d47316a08030b2515678cebbc50",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix deadlock due to mbcache entry corruption\n\nWhen manipulating xattr blocks, we can deadlock infinitely looping\ninside ext4_xattr_block_set() where we constantly keep finding xattr\nblock for reuse in mbcache but we are unable to reuse it because its\nreference count is too big. This happens because cache entry for the\nxattr block is marked as reusable (e_reusable set) although its\nreference count is too big. When this inconsistency happens, this\ninconsistent state is kept indefinitely and so ext4_xattr_block_set()\nkeeps retrying indefinitely.\n\nThe inconsistent state is caused by non-atomic update of e_reusable bit.\ne_reusable is part of a bitfield and e_reusable update can race with\nupdate of e_referenced bit in the same bitfield resulting in loss of one\nof the updates. Fix the problem by using atomic bitops instead.\n\nThis bug has been around for many years, but it became *much* easier\nto hit after commit 65f8b80053a1 (\"ext4: fix race when reusing xattr\nblocks\")."
    }
  ],
  "lastModified": "2026-08-04T10:18:20.807",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}