Critical Update for Windows Media Player (KB828026)

This update contains a change to the behavior of Windows Media Player’s ability to launch URLs in the local computer zone from other zones. You can help protect your computer by installing this update from Microsoft.

When a content owner creates an audio or video stream, they can add script commands (such as URL script commands and custom script commands) to be encoded in the stream. When the stream is played back, the script commands can trigger events in an embedded player program, or they can open your browser and then navigate to a Web page. This behavior is by design. This update changes the way that Windows Media Player handles URL script commands that are embedded in a stream.

Microsoft
Critical Update for Windows Media Player (All Versions)
for Windows 2000, Windows XP, and Windows Server 2003
(KB828026)