CVE-2026-101304: Multiple jail filesystem root escapes

High 7.1 EPSS 0.1% FreeBSD

When fdescfs(4) was mounted in a jail with the "nodup" option, opening /dev/fd/N returned a descriptor that did not inherit FD_RESOLVE_BENEATH or the Capsicum capability rights of descriptor N. A process in a jail that has received a directory file descriptor from another jail can use these techniques to escape the jail's filesystem root restriction.

CVE-2026-101304CVE identifier
7.1CVSS 3.1 base score (high)
0.1%EPSS: chance of exploitation in the next 30 days (higher than 4% of CVEs)
2026-10-15published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

What to do now

Check whether you run FreeBSD and which version (commands below).
Install the fixed version for your system: see “Patch it” below.
Reboot when the advisory touches the kernel or core libraries; otherwise restart the affected daemons (the advisory says which)

Affected and fixed versions

Affected:

FreeBSD FreeBSD 15.1-RELEASE to before p4
FreeBSD FreeBSD 15.0-RELEASE to before p14
FreeBSD FreeBSD 14.5-RELEASE to before p1
FreeBSD FreeBSD 14.4-RELEASE to before p10

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

FreeBSD

base system: freebsd-update fetch install; packages: pkg upgrade

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

Sources

Page generated automatically from official sources on 2026-11-03 18:05 UTC. Always confirm with your vendor's advisory.