By default, jailed processes cannot mount filesystems, including nullfs(4). However, the allow.mount.nullfs option enables mounting nullfs filesystems, subject to privilege checks.

If a privileged user within a jail is able to nullfs-mount directories, a limitation of the kernel's path lookup logic allows that user to escape the jail's chroot, yielding access to the full filesystem of the host or parent jail.

In a jail configured to allow nullfs(4) mounts from within the jail, the jailed root user can escape the jail's filesystem root.

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History

Tue, 10 Mar 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Tue, 10 Mar 2026 14:15:00 +0000

Type Values Removed Values Added
First Time appeared Freebsd
Freebsd freebsd
Vendors & Products Freebsd
Freebsd freebsd

Mon, 09 Mar 2026 12:00:00 +0000

Type Values Removed Values Added
Description By default, jailed processes cannot mount filesystems, including nullfs(4). However, the allow.mount.nullfs option enables mounting nullfs filesystems, subject to privilege checks. If a privileged user within a jail is able to nullfs-mount directories, a limitation of the kernel's path lookup logic allows that user to escape the jail's chroot, yielding access to the full filesystem of the host or parent jail. In a jail configured to allow nullfs(4) mounts from within the jail, the jailed root user can escape the jail's filesystem root.
Title Jail escape by a privileged user via nullfs
Weaknesses CWE-269
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: freebsd

Published:

Updated: 2026-03-10T18:59:55.413Z

Reserved: 2026-01-26T15:57:03.264Z

Link: CVE-2025-15547

cve-icon Vulnrichment

Updated: 2026-03-10T18:58:43.372Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-03-09T12:16:11.403

Modified: 2026-03-10T20:16:19.450

Link: CVE-2025-15547

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-03-10T14:07:28Z

Weaknesses