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Fencer Vulns
critical 9.8

CVE-2021-30189 json

CODESYS V2 Web-Server before 1.1.9.20 has a Stack-based Buffer Overflow.

published 2021-05-25 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-17121

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

CODESYS V2 Web-Server before 1.1.9.20 has a Stack-based Buffer Overflow.

Patch / fix

  • codesys v2_web_server 1.1.9.20
  • wago 750-893_firmware fw08
  • wago 750-891_firmware fw08
  • wago 750-890_firmware fw08
  • wago 750-889_firmware fw15
  • wago 750-885_firmware fw15
  • wago 750-882_firmware fw15
  • wago 750-881_firmware fw15
  • wago 750-880_firmware fw16
  • wago 750-862_firmware fw08
  • wago 750-852_firmware fw15
  • wago 750-832_firmware fw08
  • wago 750-831_firmware fw15
  • wago 750-829_firmware fw15
  • wago 750-8202_firmware 03.06.19_\(18\)
  • wago 750-8203_firmware 03.06.19_\(18\)
  • wago 750-8204_firmware 03.06.19_\(18\)
  • wago 750-8206_firmware 03.06.19_\(18\)
  • wago 750-8207_firmware 03.06.19_\(18\)
  • wago 750-8208_firmware 03.06.19_\(18\)

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-173-02 updated cvss 9.8

CODESYS V2 web server

  • CODESYS, GmbH CODESYS reports all CODESYS V2 web servers running stand-alone or as part of the CODESYS runtime system < 1.1.9.20
    affected: mitigation “Please visit the CODESYS update area for more information on how to obtain the software updates.” codesys.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

1.24% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.