Heap-based buffer overflow in the VideoConference framework in Apple Mac OS X 10.3.9 through 10.4.9 allows remote attackers to execute arbitrary code via a "crafted SIP packet when initializing an audio/video conference".
http://docs.info.apple.com/article.html?artnum=305391
http://lists.apple.com/archives/Security-announce/2007/Apr/msg00001.html
http://secunia.com/advisories/24966
http://www.kb.cert.org/vuls/id/969969
http://www.securitytracker.com/id?1017942