CVE-2026-101306: Multiple jail filesystem root escapes
SCMRIGHTS file descriptor passing did not preserve FDRESOLVEBENEATH when a descriptor was transferred. A process could clear the restriction by sending the descriptor to itself over a Unix domain socket.
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.
Affected Software
Event History
Frequently Asked Questions
Which jailed processes are exposed to this issue?
A process in a jail is exposed if it has received a directory file descriptor from another jail. It can then use Unix domain socket descriptor passing to clear the FD_RESOLVE_BENEATH restriction and escape the jail filesystem root restriction.
What does an attacker need to exploit the issue?
The attacker needs code execution in a jail and access to a directory file descriptor received from another jail. Exploitation uses SCM_RIGHTS file descriptor passing over a Unix domain socket, including sending the descriptor back to the same process.