Unspecified vulnerability in Microsoft Internet Explorer 5.01 SP4, 6 SP1, 6 on Windows XP SP2 and SP3, and 6 on Windows Server 2003 SP1 and SP2 allows remote attackers to execute arbitrary code via a web page that triggers presence of an object in memory that was (1) not properly initialized or (2) deleted, aka "Uninitialized Memory Corruption Vulnerability."