How severe is CVE-2019-5636?

CVE-2019-5636 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2019-5636 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-5636?

CVE-2019-5636 primarily affects Beckhoff Twincat. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-5636?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2019-5636 published?

CVE-2019-5636 was published on 2019-11-21 and last updated on 2026-06-17.

CVE-2019-5636

CVE-2019-5636 is a medium-severity vulnerability in Beckhoff Twincat with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-404.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-404
Affected product: Beckhoff Twincat
Published: 2019-11-21
Last modified: 2026-06-17

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).

Frequently asked questions

What is 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).
How severe is CVE-2019-5636?: CVE-2019-5636 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2019-5636 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-5636?: CVE-2019-5636 primarily affects Beckhoff Twincat. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-5636?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-5636 published?: CVE-2019-5636 was published on 2019-11-21 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:beckhoff:twincat:2.0:build2304:*:*:*:*:*:*
cpe:2.3:a:beckhoff:twincat:3.1:build4024.0:*:*:*:*:*:*

More vulnerabilities in Beckhoff Twincat

CVE-2019-16871 — Critical (CVSS 9.8): Beckhoff Embedded Windows PLCs through 3.1.4024.0, and Beckhoff Twincat on Windows Engineering stations, allow an…
CVE-2017-16726 — Critical (CVSS 9.1): Beckhoff TwinCAT supports communication over ADS. ADS is a protocol for industrial automation in protected…
CVE-2014-5415 — Critical (CVSS 9.1): Beckhoff Embedded PC images before 2014-10-22 and Automation Device Specification (ADS) TwinCAT components might allow…
CVE-2014-5414 — Critical (CVSS 9.1): Beckhoff Embedded PC images before 2014-10-22 and Automation Device Specification (ADS) TwinCAT components do not…
CVE-2018-7502 — High (CVSS 7.8): Kernel drivers in Beckhoff TwinCAT 3.1 Build 4022.4, TwinCAT 2.11 R3 2259, and TwinCAT 3.1 lack proper validation of…
CVE-2019-5637 — High (CVSS 7.5): When Beckhoff TwinCAT is configured to use the Profinet driver, a denial of service of the controller could be reached…

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