CVE-2026-101304

Multiple jail filesystem root escapes

State: Published
Severity: 7.1 High
Published: Oct 15, 2026
Updated: Oct 20, 2026
Reserved: Sep 28, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	7.1 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N	CISA-ADP

Weaknesses

CWE-273 Improper Check for Dropped Privileges

Affected Products

Product	Versions
FreeBSDFreeBSD	15.1-RELEASE to before p4Affected 15.0-RELEASE to before p14Affected 14.5-RELEASE to before p1Affected 14.4-RELEASE to before p10Affected

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:66.jail.ascvendor-advisory

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