Microsoft DirectX 8.1 through 9.0c, and DirectX on Microsoft XP SP2 and SP3, Server 2003 SP1 and SP2, Vista Gold and SP1, and Server 2008, does not properly perform MJPEG error checking, which allows remote attackers to execute arbitrary code via a crafted MJPEG stream in a (1) AVI or (2) ASF file, aka the "MJPEG Decoder Vulnerability."