The remote Windows host contains an application that is affected by a buffer overflow vulnerability.
The version of QuickTime installed on the remote Windows host is older than 7.4.1. Such versions contain a heap-based buffer overflow in the application's handling of HTTP responses when RTSP tunneling is enabled. If an attacker can trick a user into visiting a specially crafted webpage, arbitrary code could be executed on the remote host subject to the user's privileges.
Either use QuickTime's Software Update preference to upgrade to the latest version or manually upgrade to QuickTime 7.4.1 or later.