Apple released QuickTime 7.5 late on Monday, an update that appear to focus on security issues and compatibility improvements, despite its 7.4.5 yo 7.5 bump. The security-related update notes list five vulnerabilities that were addressed, all of them serious in nature, while the main patch note in Software Update simply say, "QuickTime 7.5 improves application compatibility and addresses security issues. "
The update is a 60 MB download for Mac OS X 10.5.x, and can be found in Software Update. Windows users can look for the update under Update in iTunes.