Still using Apple’s QuickTime for viewing video files? It’s time to move over to something like VLC following recent press reports that there’s no patch on the digital horizon.
The short explanation is that a vulnerability was found in the QuickTime program but Apple have decided to leave it and stop issuing patches for now, and maybe into the future.
For more information have a quick Google or a read of this article from Laptop Mag to uninstall QT.