{
  "cveId": "CVE-2026-78409",
  "url": "https://patchblox.com/security/cve/CVE-2026-78409",
  "summary": "CVE-2026-78409 is fixed in util-linux on 1 platform by DEBIAN-CVE-2026-78409 (version 2.42.3-1), released September 17, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "util-linux: The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirecto...",
  "description": "The X-mount.subdir option uses a detached-tree fast path on Linux 6.15 and later and passes the configured subdirectory to open_tree() with AT_SYMLINK_NOFOLLOW. That flag does not stop intermediate symlink traversal or keep resolution inside the newly mounted filesystem. A local unprivileged user with an fstab-authorized X-mount.subdir entry can attach a host path at the intended mountpoint.",
  "published": "2026-09-02T16:17:23Z",
  "severity": "high",
  "cvss": 7,
  "cvssVector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00189,
  "epssPercentile": 0.08617,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "util-linux",
      "release": "Debian 14",
      "fixedVersion": "2.42.3-1",
      "fix": "DEBIAN-CVE-2026-78409",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-78409",
      "released": "2026-09-17T18:08:56Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}