What is CVE-2021-30190?

CVE-2021-30190 is a critical-severity vulnerability in Codesys V2 Web Server, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2021-05-25.

How severe is CVE-2021-30190?

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

Is CVE-2021-30190 known to be exploited?

9 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Auth bypass in Codesys V2 Web Server

CVE-2021-30190

CODESYS V2 Web-Server before 1.1.9.20 has Improper Access Control.

Vulnerability class: Broken Authentication

Published 2021-05-25 · 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: 0.014 (71.4th percentile), scored 2026-10-07.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 71.4% 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: 0.014 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

Public proof-of-concept exploits

References

customers.codesys.com/index.php (Permissions Required, Vendor Advisory)
customers.codesys.com/index.php (Vendor Advisory)

Frequently asked questions

What is CVE-2021-30190?: CVE-2021-30190 is a critical-severity vulnerability in Codesys V2 Web Server, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2021-05-25.
How severe is CVE-2021-30190?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-30190 known to be exploited?: 9 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.