CVE-2020-12526
BECKHOFF: DoS-Vulnerability for TwinCAT OPC UA Server and IPC Diagnostics UA Server
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
BECKHOFF: DoS-Vulnerability for TwinCAT OPC UA Server and IPC Diagnostics UA Server
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.
- Record
CVE-2020-12526- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2020-4828
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.
- Record
EUVD-2020-4828- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-53xf-f462-gx5v No score
TwinCAT OPC UA Server in versions up to 2.3.0.12 and IPC Diagnostics UA Server in versions up to...
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.
- Record
GHSA-53xf-f462-gx5v- Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2020-12526- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-20
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-12526 is a medium vulnerability (CVSS 5.3) in Beckhoff Ipc Diagnostics Ua Server, published May 13, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.95%, the 61st percentile. No source names a fixed version.