Microsoft Internet Explorer - Code Injection
The URL validation functionality in Microsoft Internet Explorer 5.01, 6, 6 SP1, 7 and 8, and the ShellExecute API function in Windows 2000 SP4, XP SP2 and SP3, and Server 2003 SP2, does not properly process input parameters, which allows remote attackers to execute arbitrary local programs via a crafted URL, aka "URL Validation Vulnerability."