CVE-2021-34593

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.

• CWE-755

• 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

Published

Oct 26, 2021

Last Modified

Jun 17, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
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