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CVE-2021-34586

CODESYS V2 web server: crafted requests could trigger a null pointer dereference (DoS)

Published: Oct 26, 2021Updated: Aug 15, 2025 Sources: CVE List NVDCWE-476
NVD MITRE
7.5CVSSHIGH
EPSS Score
13.1%
Top 4.1%
CISA KEV
Not in KEV
Exploits
1 Known
Remediation
Patch Available

Description

In the CODESYS V2 web server prior to V1.1.9.22 crafted web server requests may cause a Null pointer dereference in the CODESYS web server and may result in a denial-of-service condition.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-476

Affected Products

CODESYS V2CODESYSICS / OT / IoT
750-823 firmwarewagoICS / OT / IoT
750-829 firmwarewagoICS / OT / IoT
750-831 firmwarewagoICS / OT / IoT
750-832 firmwarewagoICS / OT / IoT
codesysoss-projectDEICS / OT / IoTaka codesys gmbh
wagocommercialDEICS / OT / IoT
and 24 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

1 exploit source identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available

MITRE ATT&CK

2 techniques
Impact
Initial Access
View detailed technique mapping

References

https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=16876&token=a3f1d937f95e7034879f4f2ea8e5a99b168256a7&download=
customers.codesys.com
https://www.tenable.com/security/research/tra-2021-47
tenable.com

Timeline

Published
Oct 26, 2021
Last Updated
Aug 15, 2025

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