CVE-2025-15547

By default, jailed processes cannot mount filesystems, including nullfs(4). However, the allow.mount.nullfs option enables mounting nullfs filesystems, subject to privilege checks.<br /> <br /> If a privileged user within a jail is able to nullfs-mount directories, a limitation of the kernel&amp;#39;s path lookup logic allows that user to escape the jail&amp;#39;s chroot, yielding access to the full filesystem of the host or parent jail.<br /> <br /> In a jail configured to allow nullfs(4) mounts from within the jail, the jailed root user can escape the jail&amp;#39;s filesystem root.