The security-related fixes impact both the Mac OS X and Windows versions of QuickTime, and address situations where maliciously crafted media files could cause unexpected application termination, or allow an attacker to execute arbitrary code.
The update is available via Appleis Software Update application, or as a stand-alone installer for Mac OS X and Windows.
QuickTime is free, and available for download at the Apple Web site. QuickTime Pro, which adds the ability to edit and encode media files, is priced at US$29.99.