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."