Microsoft .NET Framework 1.0 SP3 1.1 SP1 2.0 SP2 3.5.1 and 4 and Silverlight 4 before 4.0.60831 does not properly restrict inheritance which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (aka XBAP) (2) a crafted ASP.NET application (3) a crafted .NET Framework application or (4) a crafted Silverlight application aka \.NET Framework Class Inheritance Vulnerability.\