GHSA-HGQ3-CHG9-C98J

Vulnerability from github – Published: 2026-01-13 18:31 – Updated: 2026-01-19 15:30
VLAI?
Details

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

fsnotify: do not generate ACCESS/MODIFY events on child for special files

inotify/fanotify do not allow users with no read access to a file to subscribe to events (e.g. IN_ACCESS/IN_MODIFY), but they do allow the same user to subscribe for watching events on children when the user has access to the parent directory (e.g. /dev).

Users with no read access to a file but with read access to its parent directory can still stat the file and see if it was accessed/modified via atime/mtime change.

The same is not true for special files (e.g. /dev/null). Users will not generally observe atime/mtime changes when other users read/write to special files, only when someone sets atime/mtime via utimensat().

Align fsnotify events with this stat behavior and do not generate ACCESS/MODIFY events to parent watchers on read/write of special files. The events are still generated to parent watchers on utimensat(). This closes some side-channels that could be possibly used for information exfiltration [1].

[1] https://snee.la/pdf/pubs/file-notification-attacks.pdf

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68788"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-01-13T16:15:58Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfsnotify: do not generate ACCESS/MODIFY events on child for special files\n\ninotify/fanotify do not allow users with no read access to a file to\nsubscribe to events (e.g. IN_ACCESS/IN_MODIFY), but they do allow the\nsame user to subscribe for watching events on children when the user\nhas access to the parent directory (e.g. /dev).\n\nUsers with no read access to a file but with read access to its parent\ndirectory can still stat the file and see if it was accessed/modified\nvia atime/mtime change.\n\nThe same is not true for special files (e.g. /dev/null). Users will not\ngenerally observe atime/mtime changes when other users read/write to\nspecial files, only when someone sets atime/mtime via utimensat().\n\nAlign fsnotify events with this stat behavior and do not generate\nACCESS/MODIFY events to parent watchers on read/write of special files.\nThe events are still generated to parent watchers on utimensat(). This\ncloses some side-channels that could be possibly used for information\nexfiltration [1].\n\n[1] https://snee.la/pdf/pubs/file-notification-attacks.pdf",
  "id": "GHSA-hgq3-chg9-c98j",
  "modified": "2026-01-19T15:30:35Z",
  "published": "2026-01-13T18:31:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68788"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/635bc4def026a24e071436f4f356ea08c0eed6ff"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6a7d7d96eeeab7af2bd01afbb3d9878a11a13d91"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7a93edb23bcf07a3aaf8b598edfc2faa8fbcc0b6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/82f7416bcbd951549e758d15fc1a96a5afc2e900"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/859bdf438f01d9aa7f84b09c1202d548c7cad9e8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/df2711544b050aba703e6da418c53c7dc5d443ca"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e0643d46759db8b84c0504a676043e5e341b6c81"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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