How severe is CVE-2019-16871?

CVE-2019-16871 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-16871 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-16871?

CVE-2019-16871 primarily affects Beckhoff Twincat. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-16871?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2019-16871 published?

CVE-2019-16871 was published on 2019-12-19 and last updated on 2026-06-17.

CVE-2019-16871

CVE-2019-16871 is a critical-severity vulnerability in Beckhoff Twincat with a CVSS 3.x base score of 9.8. 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-290.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 9.3
EPSS exploit prediction: 5% (92nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-290
Affected product: Beckhoff Twincat
Published: 2019-12-19
Last modified: 2026-06-17

Description

Beckhoff Embedded Windows PLCs through 3.1.4024.0, and Beckhoff Twincat on Windows Engineering stations, allow an attacker to achieve Remote Code Execution (as SYSTEM) via the Beckhoff ADS protocol.

Frequently asked questions

What is CVE-2019-16871?: Beckhoff Embedded Windows PLCs through 3.1.4024.0, and Beckhoff Twincat on Windows Engineering stations, allow an attacker to achieve Remote Code Execution (as SYSTEM) via the Beckhoff ADS protocol.
How severe is CVE-2019-16871?: CVE-2019-16871 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-16871 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-16871?: CVE-2019-16871 primarily affects Beckhoff Twincat. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-16871?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2019-16871 published?: CVE-2019-16871 was published on 2019-12-19 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:beckhoff:twincat:*:*:*:*:*:*:*:*
cpe:2.3:a:beckhoff:twincat:2.0:*:*:*:*:*:*:*
cpe:2.3:a:beckhoff:twincat:3.1:build_4022:*:*:*:*:*:*
cpe:2.3:a:beckhoff:twincat:3.1:build_4024.0:*:*:*:*:*:*

More vulnerabilities in Beckhoff Twincat

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…
CVE-2017-16718 — Medium (CVSS 5.9): Beckhoff TwinCAT 3 supports communication over ADS. ADS is a protocol for industrial automation in protected…

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