CVE-2025-15547

Jail escape by a privileged user via nullfs

Published Mar 9, 2026 CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
CPEs cpe:2.3:o:freebsd:freebsd:13.5:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p6:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p7:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:13.5:p8:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p6:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:14.3:p7:*:*:*:*:*:*
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'}

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

Sources

Status
PUBLISHED
Assigner
freebsd
Published
Updated
Mar 10, 2026, 6:59 PM
Reserved
Jan 26, 2026, 3:57 PM
Status
Analyzed
Published
Mar 9, 2026, 12:16 PM
Modified
Jun 17, 2026, 8:37 AM