The .NET Remoting implementation in Microsoft .NET Framework 1.1 SP1, 2.0 SP2, 3.5, 3.5.1, 4, 4.5, and 4.5.1 does not properly restrict memory access, which allows remote attackers to execute arbitrary code via vectors involving malformed objects, aka "TypeFilterLevel Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-026