Integer overflow in QuickTime in Apple Mac OS X before 10.6.8 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted movie file.
http://support.apple.com/kb/HT4723
http://lists.apple.com/archives/security-announce/2011//Jun/msg00000.html
http://lists.apple.com/archives/security-announce/2011//Aug/msg00000.html