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.

An issue was discovered in OPC UA .NET Standard Stack and Sample Code before GitHub commit 2018-04-12, and OPC UA .NET Legacy Stack and Sample Code before GitHub commit 2018-03-13. A vulnerability in OPC UA applications can allow a remote attacker to determine a Server's private key by sending carefully constructed bad UserIdentityTokens as part of an oracle attack.

An XXE vulnerability in the OPC UA Java and .NET Legacy Stack can allow remote attackers to trigger a denial of service.

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.

wireshark: OpcUa dissector crash

Buffer overflow in OPC UA applications allows remote attackers to trigger a stack overflow with carefully structured requests.

OPC Foundation Local Discovery Server (LDS) 1.03.370 required a security update to resolve multiple vulnerabilities that allow attackers to trigger a crash by placing invalid data into the configuration file. This vulnerability requires an attacker with access to the file system where the configuration file is stored; however, if the configuration file is altered the LDS will be unavailable until it is repaired.

Unsigned versions of the DLLs distributed by the OPC Foundation may be replaced with malicious code.

The OPC Foundation Local Discovery Server (LDS) before 1.03.367 is installed as a Windows Service without adding double quotes around the opcualds.exe executable path, which might allow local users to gain privileges.