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Rockwell Automation CompactLogix 5380 ControlLogix 5580 / 1756-EN4TR Communications Module

criticalCVE-2026-9636
View CSAF Summary Successful exploitation of this vulnerability could allow an attacker to cause a denial-of-service condition. The following versions of Rockwell Automation CompactLogix 5380 ControlLogix 5580 / 1756-EN4TR Communications Module are affected: ControlLogix 5580 >=V36|<=V37 (CVE-2026-9636) CompactLogix 5380 >=V36|<=V37 (CVE-2026-9636) GuardLogix 5580 >=V36|<=V37 (CVE-2026-9636) Compact GuardLogix 5380 >=V36|<=V37 (CVE-2026-9636) 1756-EN4TR V6.001 (CVE-2026-9636) 1756-EN4TR V7.001 (CVE-2026-9636) CVSS Vendor Equipment Vulnerabilities v3 5.9 Rockwell Automation Rockwell Automation CompactLogix 5380 ControlLogix 5580 / 1756-EN4TR Communications Module Improper Check for Certificate Revocation Background Critical Infrastructure Sectors: Critical Manufacturing Countries/Areas Deployed: Worldwide Company Headquarters Location: United States Vulnerabilities Expand All + CVE-2026-9636 A security issue exists within CompactLogix 5380, ControlLogix 5580, and EN4TR 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issue stems from the controller failing to properly reject certificates signed by an intermediate certificate that has been revoked via a Certificate Revocation List (CRL).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. View CVE Details Affected Products Rockwell Automation CompactLogix 5380 ControlLogix 5580 / 1756-EN4TR Communications Module Vendor: Rockwell Automation Product Version: Rockwell Automation ControlLogix 5580: >=V36|<=V37, Rockwell Automation CompactLogix 5380: >=V36|<=V37, Rockwell Automation GuardLogix 5580: >=V36|<=V37, Rockwell Automation Compact GuardLogix 5380: >=V36|<=V37, Rockwell Automation 1756-EN4TR: V6.001, Rockwell Automation 1756-EN4TR: V7.001 Product Status: known_affected Remediations Vendor fix Rockwell Automation recommend users update to the following versions: Con

CSIRTS triage

vendor: Rockwell Automationproduct: CompactLogix 5380 ControlLogix 5580 / 1756-EN4TR Communications ModuleDenial of serviceaffected: ControlLogix 5580 >=V36|<=V37, CompactLogix 5380 >=V36|<=V37, GuardLogix 5580 >=V36|<=V37, Compact GuardLogix 5380 >=V36|<=V37, 1756-EN4TR V6.001, V7.001
What
A vulnerability could cause a denial-of-service condition.
Who is affected
Users of Rockwell Automation CompactLogix 5380, ControlLogix 5580, and 1756-EN4TR modules within the specified version range.
Urgency
Remediation is critical due to the potential for denial-of-service attacks.
Action
Update the affected modules to versions outside the specified range.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source
CISA Cybersecurity Advisories (US · national-cert · site)
Severity
critical
Published
2026-07-30
Exploitation
Not in CISA KEV at last sync

Original advisory: https://www.cisa.gov/news-events/ics-advisories/icsa-26-211-05

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2026-9636coverage & exploitation statusNVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Rockwell Automation CompactLogix

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