TI-2019-04000 Aliases CVE-2019-5636 GHSA-pv38-9q3c-3qq8

Beckhoff TwinCAT Discovery Service Denial of Service

LOW 36CWE-404Published 2019-11-21 · Updated 2024-09-17

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-404.

Summary

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).

Why it matters now

EPSS 0.01427 73rd percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Beckhoff	TwinCAT 2	2304 – 2304	—	No fix listed	CNA
Beckhoff	TwinCAT 3.1	4204.0 – 4204.0	—	No fix listed	CNA

TwinCAT 2 VendorBeckhoff Affected 2304 – 2304 Fixed in — No fix listed CNA
TwinCAT 3.1 VendorBeckhoff Affected 4204.0 – 4204.0 Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPE	Versions	Role	Vendor
cpe:2.3:a:beckhoff:twincat:2.0:build2304::::::	2.0 build2304	Vulnerable	Beckhoff
cpe:2.3:a:beckhoff:twincat:3.1:build4024.0::::::	3.1 build4024.0	Vulnerable	Beckhoff

cpe:2.3:a:beckhoff:twincat:2.0:build2304:*:*:*:*:*:* Versions 2.0 build2304 Vulnerable ·Beckhoff
cpe:2.3:a:beckhoff:twincat:3.1:build4024.0:*:*:*:*:*:* Versions 3.1 build4024.0 Vulnerable ·Beckhoff

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2019-5636
2026-10-03 Alias added: GHSA-pv38-9q3c-3qq8

References

Exploit 1

https://blog.rapid7.com/2019/10/08/r7-2019-32-denial-of-service-vulnerabilities-in-beckhoff-twincat-plc-environment-fixed/

Advisory 1

https://download.beckhoff.com/download/Document/product-security/Advisories/advisory-2019-004.pdf

TI-2011-03066 Beckhoff TwinCAT 2.11.0.2004 and earlier allows remote attackers to cause a denial of… CVSS 2.0MEDIUM 5.0
TI-2019-12580 Beckhoff Embedded Windows PLCs through 3.1.4024.0, and Beckhoff Twincat on Windows… CVSS 3.1CRITICAL 9.8
TI-2014-04414 Beckhoff Embedded PC Images and TwinCAT Components Improper Restriction of Excessive Authentication Attempts CVSS 3.1CRITICAL 9.1
TI-2014-04415 Beckhoff Embedded PC Images and TwinCAT Components Exposed Dangerous Method or Function CVSS 3.1CRITICAL 9.1
TI-2017-12294 Improper authorization in ICS-CERT Beckhoff TwinCAT CVSS 3.0CRITICAL 9.1
TI-2019-04001 Beckhoff TwinCAT Profinet Driver Divide-by-Zero Denial of Service CVSS 3.1HIGH 7.5

See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences