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Vulnerability record · CVE-2019-5636 · published 21 November 2019

CVE-2019-5636: Beckhoff twincat improper resource shutdown vulnerability

Beckhoff · Twincat

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).

7.5 CVSS 3.1 High EPSS 1.4% · top 28.1% CWE-404 · Improper resource shutdown
7.5CVSS 3.1 base score, v2 5.0
1.4%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

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).

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://blog.rapid7.com/2019/10/08/r7-2019-32-denial-of-service-vulnerabilities-in-beckhoff-twincat-plc-environment-fixe ExploitThird Party Advisory
https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2019-004.pdf Vendor Advisory
https://blog.rapid7.com/2019/10/08/r7-2019-32-denial-of-service-vulnerabilities-in-beckhoff-twincat-plc-environment-fixe ExploitThird Party Advisory
https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2019-004.pdf Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2019-5636), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.