Apple has released QuickTime 7.6.9, which fixes several critical vulnerabilities, some of which may lead to unexpected application termination or arbitrary code execution via an audio or video file. The update is available for Mac OS X 10.5.8, Windows 7, Windows Vista, and Windows XP SP2 or newer.
Note that QuickTime is incorporated into Mac OS X 10.6 and later. QuickTime 7.6.9 will not appear in Software Update to systems running Mac OS X 10.6 or later.
For more information, see http://support.apple.com/kb/HT4447