What is CVE-2021-43931?

CVE-2021-43931 is a critical-severity vulnerability in Distributed Data Systems Webhmi, classified under Improper Authentication. CVSS score: 9.8/10. Published 2021-12-06.

How severe is CVE-2021-43931?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Auth bypass in Distributed Data Systems Webhmi

CVE-2021-43931

The authentication algorithm of the WebHMI portal is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.

Vulnerability class: Broken Authentication

Published 2021-12-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.015 (73.0th percentile), scored 2026-10-04.

Low probability of exploitation in the next 30 days, but still tracked. 73rd percentile — 73.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.015 · change: +0.001

Affected products

Distributed Data Systems Webhmi — versions 4.1
Webhmi
Webhmi Firmware

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

us-cert.cisa.gov/ics/advisories/icsa-21-336-03 (US Government Resource, Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-43931?: CVE-2021-43931 is a critical-severity vulnerability in Distributed Data Systems Webhmi, classified under Improper Authentication. CVSS score: 9.8/10. Published 2021-12-06.
How severe is CVE-2021-43931?: Critical severity. CVSS v3 base score is 9.8 out of 10.