FreeBSD Security Advisory – Symlinks created using the “GNUTYPE_NAMES” tar extension can be absolute due to lack of proper sanity checks.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/52818/FreeBSD-SA-06-26.gtar.txt
Source: https://packetstormsecurity.com/files/52818/FreeBSD-SA-06-26.gtar.txt.html