Use-after-free vulnerability in the plugin in Apple QuickTime before 7.7.3 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via an HTML document with a crafted _qtactivex_ parameter in an OBJECT element.
Apple Security Advisory 2012-11-07-1 - QuickTime version 7.7.3 is now available and addresses multiple buffer overflows, memory corruption, and use after free vulnerabilities.