CVE-2020-12526: Beckhoff Ipc Diagnostics Ua Server

Medium severity, CVSS 5.3. EPSS: 1% chance of exploitation in the next 30 days.

TwinCAT OPC UA Server in versions up to 2.3.0.12 and IPC Diagnostics UA Server in versions up to 3.1.0.1 from Beckhoff Automation GmbH & Co. KG are vulnerable to denial of service attacks. The attacker needs to send several specifically crafted requests to the running OPC UA server. After some of these requests the OPC UA server is no longer responsive to any client. This is without effect to the real-time functionality of IPCs.

Affected products

• Beckhoff Ipc Diagnostics Ua Server: up to and including 3.1.0.1
• Beckhoff TF6100: up to and including 3.3.18
• Beckhoff Twincat Opc Ua Server: up to and including 2.3.0.12

Published 2021-05-13. Last modified 2026-06-17.