CVE-2026-9636: Rockwell Automation Controllogix 5580, Compactlogix 5380, Guardlogix 5580, Compact Guardlogix 5380, 1756-EN4TR

High severity, CVSS 8.2. EPSS: 0.2% chance of exploitation in the next 30 days.

A security issue exists within CompactLogix® 5380, ControlLogix® 5580, and EN4 communication modules related to CIP Security certificate revocation handling. The security issue stems from the controller failing to properly reject certificates signed by an intermediate certificate that has been revoked via a Certificate Revocation List (CRL). This could allow a network-based attacker to establish a connection using a certificate that should be untrusted, potentially bypassing CIP Security protections.

Affected products

• Rockwell Automation Controllogix 5580, Compactlogix 5380, Guardlogix 5580, Compact Guardlogix 5380, 1756-EN4TR

Published 2026-07-14. Last modified 2026-07-14.