MongoDB .NET/C# Driver vulnerable to Deserialization of Untrusted Data

Under very specific circumstances (see Required configuration section below), a privileged user is able to cause arbitrary code to be executed which may cause further disruption to services. This is specific to applications written in C#. This affects all MongoDB .NET/C# Driver versions prior to and including v2.18.0 Following configuration must be true for the vulnerability to be applicable: * Application must written in C# taking arbitrary data from users and serializing data using _t without any validation AND * Application must be running on a Windows host using the full .NET Framework, not .NET Core AND * Application must have domain model class with a property/field explicitly of type System.Object or a collection of type System.Object (against MongoDB best practice) AND * Malicious attacker must have unrestricted insert access to target database to add a _t discriminator."Following configuration must be true for the vulnerability to be applicable