FreeBSD Security Advisory FreeBSD-SA-05:18.zlib – A carefully constructed compressed data stream can result in zlib overwriting some data structures. This may cause applications to halt, resulting in a denial of service; or it may result in an attacker gaining elevated privileges.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/38927/FreeBSD-SA-05-18.zlib.txt
Source: https://packetstormsecurity.com/files/38927/FreeBSD-SA-05-18.zlib.txt.html