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CVE-2026-101304

FreeBSD: Multiple jail filesystem root escapes

FreeBSD FreeBSDOperating systems
Open in ThreatlineRecord JSON
CVSS
7.1High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.14%Chance of exploitation activity in the next 30 days, higher than 3% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published15 Oct 2026Updated 20 Oct 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

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.

Text from CVE List

Affected versions 4

  • FreeBSDaffected: 15.1-RELEASE before p4CVE List
  • FreeBSDaffected: 15.0-RELEASE before p14CVE List
  • FreeBSDaffected: 14.5-RELEASE before p1CVE List
  • FreeBSDaffected: 14.4-RELEASE before p10CVE List

References 1