A new security hole has been found in Windows Media Player 7.1 and Media Player for Windows XP (Version 8.0).
The flaw is explained as following: Flaw in Windows Media Player Skins Downloading could allow Code Execution.
Windows Media Player 9, allready available for download, is not been affected. Read More Microsoft has allready released a patch to fix this issue.
Microsoft Windows Media Player 7.1
Microsoft Windows Media Player for Windows XP (Version 8.0)
The patch is available for all languages.

Learn more about this patch over at Microsoft Technet