This indicates an attack attempt to exploit a heap-overflow vulnerability in Microsoft Windows.
This issue is caused by an error when the vulnerable systems handles a malformed WMF file. It may allow a remote attacker to execute arbitrary code by sending a crafted WMF file.
Microsoft Windows 2000 Service Pack 4
Microsoft Windows XP Service Pack 1 and Microsoft Windows XP Service Pack 2 Microsoft Windows XP Professional x64 Edition
Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service Pack
Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft Windows Server 2003 with SP1 for Itanium-based Systems
Microsoft Windows Server 2003 x64 Edition
System Compromise: Remote attackers can gain control of vulnerable systems.
Refer to the vendor's website for the suggested workaround: