FKIE_CVE-2026-31449

Vulnerability from fkie_nvd - Published: 2026-04-22 14:16 - Updated: 2026-04-23 16:17
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: validate p_idx bounds in ext4_ext_correct_indexes ext4_ext_correct_indexes() walks up the extent tree correcting index entries when the first extent in a leaf is modified. Before accessing path[k].p_idx->ei_block, there is no validation that p_idx falls within the valid range of index entries for that level. If the on-disk extent header contains a corrupted or crafted eh_entries value, p_idx can point past the end of the allocated buffer, causing a slab-out-of-bounds read. Fix this by validating path[k].p_idx against EXT_LAST_INDEX() at both access sites: before the while loop and inside it. Return -EFSCORRUPTED if the index pointer is out of range, consistent with how other bounds violations are handled in the ext4 extent tree code.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/01bf1e0b997d82c0e353b51ed74ef99698043c33
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2acb5c12ebd860f30e4faf67e6cc8c44ddfe5fe8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/407c944f217c17d4343148011acafebc604d55e1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/93f2e975ed658ce09db4d4c2877ca2c06540df83
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: validate p_idx bounds in ext4_ext_correct_indexes\n\next4_ext_correct_indexes() walks up the extent tree correcting\nindex entries when the first extent in a leaf is modified. Before\naccessing path[k].p_idx-\u003eei_block, there is no validation that\np_idx falls within the valid range of index entries for that\nlevel.\n\nIf the on-disk extent header contains a corrupted or crafted\neh_entries value, p_idx can point past the end of the allocated\nbuffer, causing a slab-out-of-bounds read.\n\nFix this by validating path[k].p_idx against EXT_LAST_INDEX() at\nboth access sites: before the while loop and inside it. Return\n-EFSCORRUPTED if the index pointer is out of range, consistent\nwith how other bounds violations are handled in the ext4 extent\ntree code."
    }
  ],
  "id": "CVE-2026-31449",
  "lastModified": "2026-04-23T16:17:41.280",
  "metrics": {},
  "published": "2026-04-22T14:16:38.933",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/01bf1e0b997d82c0e353b51ed74ef99698043c33"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2acb5c12ebd860f30e4faf67e6cc8c44ddfe5fe8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/407c944f217c17d4343148011acafebc604d55e1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/93f2e975ed658ce09db4d4c2877ca2c06540df83"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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