Unspecified vulnerability in Avifil32.dll in the Windows Media file handling functionality in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista Gold, SP1, and SP2, and Server 2008 Gold and SP2 allows remote attackers to execute arbitrary code via a malformed header in a crafted AVI file, aka "Malformed AVI Header Vulnerability."