A vulnerability has been identified in SIMATIC CP443-1 OPC UA (All versions), SIMATIC ET 200 Open Controller CPU 1515SP PC2 (All versions), SIMATIC IPC DiagMonitor (All versions), SIMATIC NET PC Software (All versions), SIMATIC RF188C (All versions), SIMATIC RF600R (All versions), SIMATIC S7-1500 CPU family (All versions >= V2.5), SIMATIC S7-1500 Software Controller (All versions >= V2.5), SIMATIC WinCC OA (All versions < V3.15-P018), SIMATIC WinCC Runtime Advanced (All versions), SIMATIC WinCC Runtime Comfort (All versions), SIMATIC WinCC Runtime HSP Comfort (All versions), SIMATIC WinCC Runtime Mobile (All versions), SINEC-NMS (All versions), SINEMA Server (All versions), SINUMERIK OPC UA Server (All versions < V2.1), TeleControl Server Basic (All versions). Specially crafted network packets sent to affected devices on port 4840/tcp could allow an unauthenticated remote attacker to cause a Denial-of-Service condition of the OPC communication or crash the device. The security vulnerability could be exploited by an attacker with network access to the affected systems. Successful exploitation requires no system privileges and no user interaction. An attacker could use the vulnerability to compromise availability of the OPC communication. At the time of advisory publication no public exploitation of this security vulnerability was known.