The seven security patches address 11 bugs, including two in its Windows Media Player software. However, no fixes were provided for two Microsoft World flaws that have been used in a small number of attacks over the past week.
Microsoft had said it would release only six patches on Tuesday, but the company added the Windows Media Format update at the last minute, after reports of attacks based on this vulnerability began surfacing. The Windows Media Format is used by Microsoft's Windows Media Player software.
In late November, security vendors warned that a buffer overflow error could occur when the Windows Media Player processed ".asx" (Advanced Stream Redirector) media files, meaning that users would first need to be tricked into opening a malicious media file for the attack to work.