CVE-2026-76992: Codesys Development System 3

High severity, CVSS 7.5. EPSS: 0.3% chance of exploitation in the next 30 days.

The CODESYS Gateway Client allocates memory based on a size field in a gateway response without enforcing an appropriate upper limit. An unauthenticated remote attacker controlling a malicious gateway can exploit this behavior to trigger excessive memory consumption, resulting in a denial-of-service condition thus leading to a total loss of availablity.

Affected products

• Codesys Development System 3: from 3.0.0.0, before 3.5.22.40 (fixed in 3.5.22.40)
• Codesys Edge Gateway For Linux: from 3.15.0.0, before 4.23.0.0 (fixed in 4.23.0.0)
• Codesys Edge Gateway For Windows: from 3.0.0.0, before 3.5.22.40 (fixed in 3.5.22.40)
• Codesys Gateway: from 3.0.0.0, before 3.5.22.40 (fixed in 3.5.22.40)
• Codesys HMI Sl: from 3.0.0.0, before 3.5.22.40 (fixed in 3.5.22.40)
• Codesys Opc Da Server Sl: from 3.0.0.0, before 3.5.22.40 (fixed in 3.5.22.40)
• Codesys Plchandler: from 3.0.0.0, before 3.5.22.40 (fixed in 3.5.22.40)
• Codesys Runtime Toolkit: from 3.0.0.0, before 3.5.22.40 (fixed in 3.5.22.40)

Published 2026-09-30. Last modified 2026-09-30.