External sources have confirmed that the said vulnerability exists in version 7.1.3 of the Quicktime software for Windows and possibly earlier versions as well. This issue has already been addressed by Apple in their latest Quicktime release. More information on how to update Quicktime can be found here.
Sometimes when you try to update your Quicktime players using the “Update Existing Software” option under the program’s help menu, it tells the user that his software is already up to date even if it isn’t. To be safe you may have to manually re-install the software using the latest installation package available at the Apple Web site.