GHSA-VW9P-6CF6-HXFH

Vulnerability from github – Published: 2026-05-01 15:30 – Updated: 2026-05-03 09:33
VLAI?
Details

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

fs/ntfs3: validate rec->used in journal-replay file record check

check_file_record() validates rec->total against the record size but never validates rec->used. The do_action() journal-replay handlers read rec->used from disk and use it to compute memmove lengths:

DeleteAttribute: memmove(attr, ..., used - asize - roff) CreateAttribute: memmove(..., attr, used - roff) change_attr_size: memmove(..., used - PtrOffset(rec, next))

When rec->used is smaller than the offset of a validated attribute, or larger than the record size, these subtractions can underflow allowing us to copy huge amounts of memory in to a 4kb buffer, generally considered a bad idea overall.

This requires a corrupted filesystem, which isn't a threat model the kernel really needs to worry about, but checking for such an obvious out-of-bounds value is good to keep things robust, especially on journal replay

Fix this up by bounding rec->used correctly.

This is much like commit b2bc7c44ed17 ("fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot") which checked different values in this same switch statement.

Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-31716"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-01T14:16:21Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: validate rec-\u003eused in journal-replay file record check\n\ncheck_file_record() validates rec-\u003etotal against the record size but\nnever validates rec-\u003eused.  The do_action() journal-replay handlers read\nrec-\u003eused from disk and use it to compute memmove lengths:\n\n  DeleteAttribute:    memmove(attr, ..., used - asize - roff)\n  CreateAttribute:    memmove(..., attr, used - roff)\n  change_attr_size:   memmove(..., used - PtrOffset(rec, next))\n\nWhen rec-\u003eused is smaller than the offset of a validated attribute, or\nlarger than the record size, these subtractions can underflow allowing\nus to copy huge amounts of memory in to a 4kb buffer, generally\nconsidered a bad idea overall.\n\nThis requires a corrupted filesystem, which isn\u0027t a threat model the\nkernel really needs to worry about, but checking for such an obvious\nout-of-bounds value is good to keep things robust, especially on journal\nreplay\n\nFix this up by bounding rec-\u003eused correctly.\n\nThis is much like commit b2bc7c44ed17 (\"fs/ntfs3: Fix slab-out-of-bounds\nread in DeleteIndexEntryRoot\") which checked different values in this\nsame switch statement.",
  "id": "GHSA-vw9p-6cf6-hxfh",
  "modified": "2026-05-03T09:33:09Z",
  "published": "2026-05-01T15:30:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31716"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0112e6279420d4005b3d57af36fb45c01b8d0116"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0ca0485e4b2e837ebb6cbd4f2451aba665a03e4b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b1613d7e2deda831a97e427d1ea586e50fe1be5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f79d0403ea20a81bc29105bba54fbcab54e8c403"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f90b8a1798b750755a9e9aee66678f0a1820bbaf"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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