CVE-2021-36765: Codesys Ethernetip

High severity, CVSS 7.5. EPSS: 1% chance of exploitation in the next 30 days.

In CODESYS EtherNetIP before 4.1.0.0, specific EtherNet/IP requests may cause a null pointer dereference in the downloaded vulnerable EtherNet/IP stack that is executed by the CODESYS Control runtime system.

Affected products

• Codesys Ethernetip: before 4.1.0.0 (fixed in 4.1.0.0)

Published 2021-08-04. Last modified 2026-06-17.