The Windows Forms (aka WinForms) component in Microsoft .NET Framework 2.0 SP2, 3.5, 3.5.1, 4, and 4.5 does not properly restrict the privileges of a callback function during object creation, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (XBAP) or (2) a crafted .NET Framework application, aka "WinForms Callback Elevation Vulnerability."