KLA10768
Security bypass vulnerability in Microsoft .NET Framework

An improper XML validation was found in Microsoft .NET Framework. By exploiting this vulnerability malicious users can bypass security restrictions. This vulnerability can be exploited remotely via signed XML file manipulations.

Microsoft .NET Framework 2.0 Service Pack 2
Microsoft .NET Framework 3.0 Service Pack 2
Microsoft .NET Framework 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1

Install necessary updates from the KB section, that are listed in your Windows Update (Windows Update usually can be accessed from the Control Panel)