CVE-2020-12526

Name: CVE-2020-12526
Creator: NVD / NIST
Published: 2021-05-13T14:15:17.457+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 0.95%

Last modified Jun 17, 2026

CVE-2020-12526 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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. EPSS estimates a 0.95% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS Probability

0.95%

56.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Beckhoff	Ipc Diagnostics Ua Server	<= 3.1.0.1
Beckhoff	Tf6100	<= 3.3.18
Beckhoff	Twincat Opc Ua Server	<= 2.3.0.12

References

https://cert.vde.com/en-us/advisories/vde-2020-051Third Party Advisory
https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2021-001.pdfVendor Advisory
https://cert.vde.com/en-us/advisories/vde-2020-051Third Party Advisory
https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2021-001.pdfVendor Advisory

Timeline

Published: May 13, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-12526?

How severe is CVE-2020-12526?

CVE-2020-12526 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.95% probability of exploitation in the next 30 days.

How do I fix CVE-2020-12526?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-12526?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST