The IPersistPropertyBag2::Read function in QTPlugin.ocx in Apple QuickTime 6.x, 7.x before 7.6.8, and other versions allows remote attackers to execute arbitrary code via the _Marshaled_pUnk attribute, which triggers unmarshalling of an untrusted pointer.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7523
http://support.apple.com/kb/ht4339
http://lists.apple.com/archives/security-announce/2010/Sep/msg00003.html