GHSA-6X6V-877J-V9FV

Vulnerability from github – Published: 2025-08-19 18:31 – Updated: 2026-01-09 15:30
VLAI?
Details

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

f2fs: fix KMSAN uninit-value in extent_info usage

KMSAN reported a use of uninitialized value in __is_extent_mergeable() and __is_back_mergeable() via the read extent tree path.

The root cause is that get_read_extent_info() only initializes three fields (fofs, blk, len) of struct extent_info, leaving the remaining fields uninitialized. This leads to undefined behavior when those fields are accessed later, especially during extent merging.

Fix it by zero-initializing the extent_info struct before population.

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-2025-38579"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-908"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-08-19T17:15:35Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix KMSAN uninit-value in extent_info usage\n\nKMSAN reported a use of uninitialized value in `__is_extent_mergeable()`\n and `__is_back_mergeable()` via the read extent tree path.\n\nThe root cause is that `get_read_extent_info()` only initializes three\nfields (`fofs`, `blk`, `len`) of `struct extent_info`, leaving the\nremaining fields uninitialized. This leads to undefined behavior\nwhen those fields are accessed later, especially during\nextent merging.\n\nFix it by zero-initializing the `extent_info` struct before population.",
  "id": "GHSA-6x6v-877j-v9fv",
  "modified": "2026-01-09T15:30:22Z",
  "published": "2025-08-19T18:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38579"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/01b6f5955e0008af6bc3a181310d2744bb349800"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08e8ab00a6d20d5544c932ee85a297d833895141"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/154467f4ad033473e5c903a03e7b9bca7df9a0fa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/44a79437309e0ee2276ac17aaedc71253af253a8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cc1615d5aba4f396cf412579928539a2b124c8a0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e68b751ec2b15d866967812c57cfdfc1eba6a269"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
    }
  ],
  "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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