Apple has released QuickTime 7.5.5 which can be downloaded and installed via QuickTime software update preferences, or from Apple Downloads.

This release contains numerous security updates. For details of security fixes and installation details see

http://support.apple.com/kb/HT3027

QuickTime 7.5.5 for Windows can be downloaded from

http://www.apple.com/support/downloads/qui...forwindows.html

select the option with or without iTunes as appropriate