OPC Foundation Local Discovery Server (LDS) through 1.04.403.478 uses a hard-coded file path to a configuration file. This allows a normal user to create a malicious file that is loaded by LDS (running as a high-privilege user).
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.