Microsoft Internet Explorer 6 SP1, 6 and 7 on Windows XP SP2 and SP3, 6 and 7 on Windows Server 2003 SP1 and SP2, 7 on Windows Vista Gold and SP1, and 7 on Windows Server 2008 does not properly handle transition errors in a request for one HTTP document followed by a request for a second HTTP document, which allows remote attackers to execute arbitrary code via vectors involving (1) multiple crafted pages on a web site or (2) a web page with crafted inline content such as banner advertisements, aka "Page Transition Memory Corruption Vulnerability."