GHSA-R88H-63MH-CC6H

Vulnerability from github – Published: 2026-06-26 21:32 – Updated: 2026-07-06 21:30
VLAI
Details

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

nilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty()

nilfs_ioctl_mark_blocks_dirty() uses bd_oblocknr to detect dead blocks by comparing it with the current block number bd_blocknr. If they differ, the block is considered dead and skipped.

However, bd_oblocknr should never be 0 since block 0 typically stores the primary superblock and is never a valid GC target block. A corrupted ioctl request with bd_oblocknr set to 0 causes the comparison to incorrectly match when the lookup returns -ENOENT and sets bd_blocknr to 0, bypassing the dead block check and calling nilfs_bmap_mark() on a non-existent block. This causes nilfs_btree_do_lookup() to return -ENOENT, triggering the WARN_ON(ret == -ENOENT).

Fix this by rejecting ioctl requests with bd_oblocknr set to 0 at the beginning of each iteration.

[ryusuke: slightly modified the commit message and comments for accuracy]

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-53320"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-26T20:17:25Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty()\n\nnilfs_ioctl_mark_blocks_dirty() uses bd_oblocknr to detect dead blocks\nby comparing it with the current block number bd_blocknr. If they differ,\nthe block is considered dead and skipped.\n\nHowever, bd_oblocknr should never be 0 since block 0 typically stores the\nprimary superblock and is never a valid GC target block. A corrupted ioctl\nrequest with bd_oblocknr set to 0 causes the comparison to incorrectly\nmatch when the lookup returns -ENOENT and sets bd_blocknr to 0, bypassing\nthe dead block check and calling nilfs_bmap_mark() on a non-existent\nblock. This causes nilfs_btree_do_lookup() to return -ENOENT, triggering\nthe WARN_ON(ret == -ENOENT).\n\nFix this by rejecting ioctl requests with bd_oblocknr set to 0 at the\nbeginning of each iteration.\n\n[ryusuke: slightly modified the commit message and comments for accuracy]",
  "id": "GHSA-r88h-63mh-cc6h",
  "modified": "2026-07-06T21:30:26Z",
  "published": "2026-06-26T21:32:18Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53320"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4525658002be3ad310b16bf8db48c8adb6a55d32"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/65e07964b4b2daf9a54e686cf0fa72d74a9648a8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/94094e70fe292c9566502772d4d4d6d6a99204b1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9472d37799a0b9ff9b99639f35961ac2f0b3c9be"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b88f905d4449b70da6bda547be546e365e44352e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/be3e5d10643d3be1cbac9d9939f220a99253f980"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e0a0c4903cbba351f0f5b5d104960d3a5b23202f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e5ff0ba4b6983cdbcc826efc201e7179ece5d46f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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