FreeBSD Security Advisory – The jail utility does not change the current working directory while imprisoning. The current working directory can be accessed by its descendants.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/90017/FreeBSD-SA-10-04.jail.txt
Source: https://packetstormsecurity.com/files/90017/FreeBSD-Security-Advisory-Insufficient-Sanitization-In-Jail.html