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.

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.

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.