Apple today released QuickTime 7.6.4 for Mac OS X Leopard and Tiger via Software Update and the QuickTime download page. A Windows version for XP and Vista is also available.
QuickTime 7.6.4 includes changes that increase reliability, improve compatibility and enhance security. This release is recommended for all QuickTime 7 users.
For detailed information on this update, please visit this website: http://support.apple.com/kb/HT3661.
For information on the security content of this update, please visit this website: http://support.apple.com/kb/HT1222.
The update addresses four security vulnerabilities across all platforms that could permit maliciously-crafted H.264, MPEG-4, or FlashPix files to execute unauthorized code.