What is CVE-2017-16726?

CVE-2017-16726 is a critical-severity vulnerability in Beckhoff Twincat, classified under Improper Authorization. CVSS score: 9.1/10. Published 2018-06-27.

How severe is CVE-2017-16726?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Auth bypass in Beckhoff Twincat

CVE-2017-16726

Beckhoff TwinCAT supports communication over ADS. ADS is a protocol for industrial automation in protected environments. ADS has not been designed to achieve security purposes and therefore does not include any encryption algorithms because of their negative effect on performance and throughput. An attacker can forge arbitrary ADS packets when legitimate ADS traffic is observable.

Published 2018-06-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.005 (41.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 41.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Beckhoff Twincat
Ics-Cert Beckhoff Twincat — versions Version 2, Version 3

Weakness classification (CWE)

References

download.beckhoff.com/download/Document/product-security/Advisories/advisory-20… (Vendor Advisory)

Frequently asked questions

What is CVE-2017-16726?: CVE-2017-16726 is a critical-severity vulnerability in Beckhoff Twincat, classified under Improper Authorization. CVSS score: 9.1/10. Published 2018-06-27.
How severe is CVE-2017-16726?: Critical severity. CVSS v3 base score is 9.1 out of 10.