GHSA-RM6F-75FW-GQ38

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-23 15:33
VLAI
Details

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

jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()

jbd2_journal_initialize_fast_commit() validates journal capacity by checking (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS). Both j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds j_last the subtraction wraps to a large value, bypassing the bounds check.

The resulting underflow corrupts j_last, j_fc_first, and j_free, leading to journal abort.

Fix by checking num_fc_blks against j_last before the subtraction, returning -EFSCORRUPTED.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-72225"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:41Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\njbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()\n\njbd2_journal_initialize_fast_commit() validates journal capacity by\nchecking (journal-\u003ej_last - num_fc_blks \u003c JBD2_MIN_JOURNAL_BLOCKS).\nBoth j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds\nj_last the subtraction wraps to a large value, bypassing the bounds\ncheck.\n\nThe resulting underflow corrupts j_last, j_fc_first, and j_free,\nleading to journal abort.\n\nFix by checking num_fc_blks against j_last before the subtraction,\nreturning -EFSCORRUPTED.",
  "id": "GHSA-rm6f-75fw-gq38",
  "modified": "2026-08-23T15:33:00Z",
  "published": "2026-08-15T06:32:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72225"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/289a2ca0c9b7eae74f93fc213b0b971669b8683d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/78955fdce8ff654e6d33a2fa90882a1e7eb26330"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a58fc10adf503969fec2007b5afe8987258046c4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aa90f00932bf572d6ef284c977c2a60b39c13bd6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e144ad0250f77e23e28949587b8b57e40dc3b512"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fb9b49618ed7296ebfad62a3835da8945f727001"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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