CVE Catalog

CVE-2026-101304

Low risk· EPSS 7%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.18%

7th percentile - higher than 7% of all known CVEs

Summary

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.

Risk Assessment

A process in a jail can bypass filesystem restrictions and access resources outside its jail, breaking isolation and potentially leading to privilege escalation.

Recommendation

Update the system to a version containing the fix for this bug. Until the patch is applied, avoid mounting fdescfs(4) with the "nodup" option in jails.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS