Microsoft .NET Framework 2.0 SP2, 3.5.1, and 4 does not properly validate the System.Net.Sockets trust level, which allows remote attackers to obtain sensitive information or trigger arbitrary outbound network traffic via (1) a crafted XAML browser application (aka XBAP), (2) a crafted ASP.NET application, or (3) a crafted .NET Framework application, aka "Socket Restriction Bypass Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12901
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-069