Unified Automation UaGateway OPC UA Server Improper Input Validation Denial-of-Service Vulnerability. This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Unified Automation UaGateway. User interaction is required to exploit this vulnerability in that the target must choose to accept a client certificate. The specific flaw exists within the processing of client certificates. The issue results from the lack of proper validation of certificate data. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-20494.