There's a buffer overflow affecting both the Windows and Mac version of Apple QuickTime 7.1.3 real-time streaming protocol (rtsp). The flaw allows remote attackers to execute arbitrary code which could allow remote access and the arbitrary execution of malicious code on compromised machines. If a user clicks a very long and specially crafted QuickTime video URL, an attacker could load malicious code onto Microsoft Windows or Apple Mac OS X machines.
At this time, there is no patch available from Apple. Users should avoid clicking URLs that begin with "rstp://." One workaround within QuickTime is to disable the rtsp:// URL handler. To do so, Mac users should open QuickTime, go to Preferences, click the Advanced tab, and select Mime Settings; once there, uncheck the box next to Streaming - Streaming Movies. For Windows users, click Edit, then Preferences, and then QuickTime Preferences. Select File Types from the pull-down menu or tab options. On the File Types page click Streaming - Streaming Movies to display additional options and uncheck the box next to RSTP stream descriptor if necessary.