CVE-2021-34593

Name: CVE-2021-34593
Creator: NVD / NIST
Published: 2021-10-26T10:15:08.013+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.65%

Last modified Jun 17, 2026

CVE-2021-34593 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. In CODESYS V2 Runtime Toolkit 32 Bit full and PLCWinNT prior to versions V2.4.7.56 unauthenticated crafted invalid requests may result in several denial-of-service conditions. Running PLC programs may be stopped, memory may be leaked, or further communication clients may be blocked from accessing the PLC.. EPSS estimates a 2.65% chance of exploitation in the next 30 days.

Description

In CODESYS V2 Runtime Toolkit 32 Bit full and PLCWinNT prior to versions V2.4.7.56 unauthenticated crafted invalid requests may result in several denial-of-service conditions. Running PLC programs may be stopped, memory may be leaked, or further communication clients may be blocked from accessing the PLC.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.65%

83.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-755

Affected Software

Vendor	Product	Versions
Wago	750-8202 Firmware	< fw20
Wago	750-8203 Firmware	< fw20
Wago	750-8204 Firmware	< fw20
Wago	750-8206 Firmware	< fw20
Wago	750-8207 Firmware	< fw20
Wago	750-8208 Firmware	< fw20
Wago	750-8210 Firmware	< fw20
Wago	750-8211 Firmware	< fw20
Wago	750-8212 Firmware	< fw20
Wago	750-8213 Firmware	< fw20
Wago	750-8214 Firmware	< fw20
Wago	750-8216 Firmware	< fw20
Wago	750-8217 Firmware	< fw20
Codesys	Plcwinnt	< 2.4.7.56
Codesys	Runtime Toolkit	< 2.4.7.56

References

http://packetstormsecurity.com/files/164716/CODESYS-2.4.7.0-Denial-Of-Service.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/165874/WAGO-750-8xxx-PLC-Denial-Of-Service-User-Enumeration.htmlExploit, Third Party Advisory, VDB Entry
http://seclists.org/fulldisclosure/2021/Oct/64Mailing List, Third Party Advisory
https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=16877&token=8faab0fc1e069f4edfca5d5aba8146139f67a175&download=Vendor Advisory
http://packetstormsecurity.com/files/164716/CODESYS-2.4.7.0-Denial-Of-Service.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/165874/WAGO-750-8xxx-PLC-Denial-Of-Service-User-Enumeration.htmlExploit, Third Party Advisory, VDB Entry
http://seclists.org/fulldisclosure/2021/Oct/64Mailing List, Third Party Advisory
https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=16877&token=8faab0fc1e069f4edfca5d5aba8146139f67a175&download=Vendor Advisory

Timeline

Published: Oct 26, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-34593?

How severe is CVE-2021-34593?

CVE-2021-34593 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.65% probability of exploitation in the next 30 days.

How do I fix CVE-2021-34593?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-34593?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST