CVE-2026-9636

ControlLogix® 5580, CompactLogix® 5380, VulnerabilityCVSS 8.2

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issue stems from the controller failing to properly reject certificates signed by an intermediate certificate that has been revoked via a Certificate Revocation List (CRL).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.

No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.

Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.

CVE-2026-9636 ControlLogix® 5580, CompactLogix® 5380, Vulnerability

Severity metrics

CVSS 4.0 : 8.2 HIGH

Attack vectorNetwork (remote)

Attack complexityHigh

Attack requirementsPresent

Privileges requiredNone

User interactionNone

Confidentiality impactHigh

Integrity impactNone

Availability impactNone

Subsequent confidentialityNone

Subsequent integrityNone

Subsequent availabilityNone

Vector: AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Affected & fixed versions by distribution

Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.

No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.

Sources

Advisory NVD CVE.org

Published 2026-07-14 · updated 2026-07-26 · source: NVD