The OPC UA .NET Standard Reference Server before 1.4.371.86. places sensitive information into an error message that may be seen remotely.
A Privilege Elevation vulnerability in OPC UA .NET Standard Stack 1.4.363.107 could allow a rogue application to establish a secure connection.
In OPC Foundation OPC UA .NET Standard codebase 1.4.357.28, servers do not create sufficiently random numbers in OPCFoundation.NetStandard.Opc.Ua before 1.4.359.31, which allows man in the middle attackers to reuse encrypted user credentials sent over the network.
Failure to validate certificates in OPC Foundation UA Client Applications communicating without security allows attackers with control over a piece of network infrastructure to decrypt passwords.