Apple have released QuickTime 7.6.2 that contains security updates.

This version can be downloaded and installed via Software Update preferences, or from Apple Downloads.

QuickTime for Windows can be downloaded from Apple downloads at

http://support.apple.com/downloads/QuickTi...6_2_for_Windows

select the option with or without iTunes as appropriate.

For full details on the security content of this update see this Apple document:

http://support.apple.com/kb/HT3591