Critical Denial-of-Service Vulnerability in Rockwell Automation CompactLogix 5370 Controllers

Critical DoS Vulnerability Discovered in Rockwell Automation CompactLogix 5370 Controllers

The Cybersecurity and Infrastructure Security Agency (CISA) has issued an advisory (ICSA-26-022-03) warning of a critical denial-of-service (DoS) vulnerability affecting Rockwell Automation CompactLogix 5370 programmable logic controllers (PLCs). Successful exploitation of this flaw could enable threat actors to disrupt industrial operations by causing affected devices to enter a fault state.

Technical Details

The vulnerability impacts the following versions of CompactLogix 5370 controllers:

• CompactLogix 5370 L1 (1769-L1 series)
• CompactLogix 5370 L2 (1769-L2 series)
• CompactLogix 5370 L3 (1769-L3 series)

While specific technical details remain undisclosed, CISA’s advisory indicates that the flaw could be exploited to trigger a DoS condition, potentially halting critical industrial processes. The vulnerability has been assigned CVE-2026-XXXX (exact CVE pending confirmation).

Impact Analysis

Industrial control systems (ICS) relying on CompactLogix 5370 controllers are at risk of operational disruption if exploited. A DoS attack could lead to:

• Unplanned downtime in manufacturing, energy, or water treatment facilities
• Safety risks if critical monitoring or control functions fail
• Financial losses due to halted production or recovery efforts

Given the widespread use of Rockwell Automation devices in OT environments, this vulnerability poses a significant threat to industrial cybersecurity.

Mitigation and Recommendations

CISA urges organizations using affected CompactLogix 5370 controllers to:

1. Apply Rockwell Automation’s patches as soon as they become available.
2. Restrict network access to vulnerable devices using firewalls or segmentation.
3. Monitor for unusual traffic targeting ICS networks.
4. Implement backup and recovery plans to minimize downtime in case of an attack.

For further details, refer to the CSAF advisory.

Stay updated on ICS vulnerabilities by following CISA’s Industrial Control Systems Advisories.