The LZW stream decompression functionality in ORMELEMS.DLL in Microsoft Visio 2002 SP2, 2003 SP3, and 2007 SP2 allows remote attackers to execute arbitrary code via a Visio file with a malformed VisioDocument stream that triggers an exception handler that accesses an object that has not been fully initialized, which triggers memory corruption, aka "Visio Object Memory Corruption Vulnerability."