Format string vulnerability in Apple iChat 3.1.6 allows remote attackers to cause a denial of service (null pointer dereference and application crash) and possibly execute arbitrary code via format string specifiers in an aim:// URI.
https://exchange.xforce.ibmcloud.com/vulnerabilities/31679
http://www.vupen.com/english/advisories/2007/0274
http://www.us-cert.gov/cas/techalerts/TA07-047A.html
http://www.securitytracker.com/id?1017661
http://www.securityfocus.com/bid/22146
http://www.kb.cert.org/vuls/id/794752
http://secunia.com/advisories/24198
http://lists.apple.com/archives/Security-announce/2007/Feb/msg00000.html