SB20260422184 - Jail escape via nullfs in FreeBSD
Published: April 22, 2026
Security Bulletin ID
SB20260422184
Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Buffer overflow (CVE-ID: CVE-2025-15547)
The vulnerability allows a local privileged user to escape the jail filesystem root.
The vulnerability exists due to improper restriction of operations within the bounds of a memory buffer in the kernel path lookup logic when mounting nullfs filesystems from within a jail. A local privileged user can mount a nullfs directory to escape the jail filesystem root.
Only jails configured with the allow.mount.nullfs option are vulnerable.
Remediation
Install update from vendor's website.