CVE-2021-30190Network attack vector

Unauthenticated PLC value access via unchecked subordinate requests

Published May 25, 2021 · Updated Aug 3, 2024

Improper access control in CODESYS V2 Web-Server before 1.1.9.20 allows remote attackers to read or write PLC values without authentication. The WebVisu user-management layer forwards subordinate value-read and value-write requests to the CODESYS Control runtime even when authentication fails. Network access to the web server is sufficient to bypass visualization-page controls and alter or disclose controller values.

CVSS severity10.0
Critical
EPSS probability1.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in CODESYS V2 Web-Server before 1.1.9.20 allows remote attackers to read or write PLC values without authentication. The WebVisu user-management layer forwards subordinate value-read and value-write requests to the CODESYS Control runtime even when authentication fails. Network access to the web server is sufficient to bypass visualization-page controls and alter or disclose controller values.

The record

CVE
CVE-2021-30190
Published
May 25, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-284, T0866
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8INCIBE-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5INCIBE-CERTAV:N/AC:L/Au:N/C:P/I:P/A:P
10.0CODESYS GmbHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T0866Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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