HOMEVULNERABILITIESCVE-2021-30193
CRITICAL

CVE-2021-30193

CWE-787Published: May 25, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

CODESYS V2 Web-Server before 1.1.9.20 has an Out-of-bounds Write.

NVD Source

Technical Analysis

CVE-2021-30193 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

codesys1 product(s)
v2 web server
wago54 product(s)
750-893 firmware750-893750-891 firmware750-891750-890 firmware750-890750-889 firmware750-889750-885 firmware750-885750-882 firmware750-882+42
Source: NVD CPE · 55 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
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Official Patches & Advisories

All References (4)

Quick Facts

CVE IDCVE-2021-30193
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-787
CISA KEVNo
Affected2 vendor(s)
PublishedMay 25, 2021

Related CVEs (CWE-787)

Recommended Actions

  • Apply vendor patches immediately
  • Monitor CVE-2021-30193 in threat intel feeds
  • Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.