CVE-2019-5636

When a Beckhoff TwinCAT Runtime receives a malformed UDP packet, the ADS Discovery Service shuts down. Note that the TwinCAT devices are still performing as normal. This issue affects TwinCAT 2 version 2304 (and prior) and TwinCAT 3.1 version 4204.0 (and prior).

• CWE-404
• CWE-404

• https://blog.rapid7.com/2019/10/08/r7-2019-32-denial-of-service-vulnerabilities-in-beckhoff-twincat-plc-environment-fixed/Exploit, Third Party Advisory
• https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2019-004.pdfVendor Advisory
• https://blog.rapid7.com/2019/10/08/r7-2019-32-denial-of-service-vulnerabilities-in-beckhoff-twincat-plc-environment-fixed/Exploit, Third Party Advisory
• https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2019-004.pdfVendor Advisory

Published

Nov 21, 2019

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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