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Vulnerability record · CVE-2019-16871 · published 19 December 2019

CVE-2019-16871: Beckhoff twincat authentication bypass by spoofing vulnerability

Beckhoff · Twincat

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.

9.8 CVSS 3.1 Critical EPSS 5.3% · top 7.7% CWE-290 · Authentication bypass by spoofing
9.8CVSS 3.1 base score, v2 9.3
5.3%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

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.

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

Affected products

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

References

LinkTags
https://download.beckhoff.com/download/document/product-security/Advisories/advisory-2017-001.pdf Vendor Advisory
https://www.ic4.be/2019/12/18/beckhoff-cve-2019-16871/#more-648 ExploitThird Party Advisory
https://download.beckhoff.com/download/document/product-security/Advisories/advisory-2017-001.pdf Vendor Advisory
https://www.ic4.be/2019/12/18/beckhoff-cve-2019-16871/#more-648 ExploitThird Party Advisory

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Related vulnerabilities

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

9.1CVE-2017-16726Beckhoff twincat improper authorization vulnerabilityBeckhoff TwinCAT supports communication over ADS. ADS is a protocol for industrial automation in protected environments. ADS has not been designed to…EPSS 0.51%9.1CVE-2014-5415Beckhoff embedded pc images permissions and access controls vulnerabilityBeckhoff Embedded PC images before 2014-10-22 and Automation Device Specification (ADS) TwinCAT components might allow remote attackers to obtain acc…EPSS 4.3%9.1CVE-2014-5414Beckhoff embedded pc images improper restriction of authentication attempts vulnerabilityBeckhoff Embedded PC images before 2014-10-22 and Automation Device Specification (ADS) TwinCAT components do not restrict the number of authenticati…EPSS 4.8%7.8CVE-2018-7502Beckhoff twincat improper input validation vulnerabilityKernel drivers in Beckhoff TwinCAT 3.1 Build 4022.4, TwinCAT 2.11 R3 2259, and TwinCAT 3.1 lack proper validation of user-supplied pointer values. An…EPSS 0.56%7.5CVE-2019-5636Beckhoff twincat improper resource shutdown vulnerabilityWhen a Beckhoff TwinCAT Runtime receives a malformed UDP packet, the ADS Discovery Service shuts down. Note that the TwinCAT devices are still perfor…EPSS 1.4%7.5CVE-2019-5637Beckhoff twincat divide by zero vulnerabilityWhen Beckhoff TwinCAT is configured to use the Profinet driver, a denial of service of the controller could be reached by sending a malformed UDP pac…EPSS 1.4%5.9CVE-2017-16718Beckhoff twincat insufficiently protected credentials vulnerabilityBeckhoff TwinCAT 3 supports communication over ADS. ADS is a protocol for industrial automation in protected environments. This protocol uses user co…EPSS 0.42%5.3CVE-2020-12494Beckhoff twincat driver vulnerabilityBeckhoff's TwinCAT RT network driver for Intel 8254x and 8255x is providing EtherCAT functionality. The driver implements real-time features. Except …EPSS 1.0%

Source: NIST National Vulnerability Database (record CVE-2019-16871), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.