CVE-2025-9124 is a denial-of-service vulnerability identified in Rockwell Automation's Compact GuardLogix® 5370 controllers, affecting firmware versions 30.012 and earlier. The root cause is an uncaught exception triggered when the device receives a specially crafted CIP (Common Industrial Protocol) unconnected explicit message. This crafted message causes the controller to experience a major non-recoverable fault, effectively crashing or halting the device’s operation. The vulnerability does not require any authentication or user interaction, and can be exploited remotely over the network, making it highly accessible to attackers. The impact is primarily on availability, as the device becomes non-functional until manually reset or repaired. The vulnerability is categorized under CWE-248 (Uncaught Exception), indicating improper handling of unexpected conditions in the software. While no known exploits have been observed in the wild, the vulnerability’s high CVSS 4.0 score of 8.7 reflects its critical impact on industrial control systems. Rockwell Automation Compact GuardLogix® 5370 controllers are widely used in industrial automation environments, including manufacturing plants, utilities, and critical infrastructure sectors. Disruption of these controllers can lead to production downtime, safety hazards, and operational losses. The lack of a patch at the time of disclosure necessitates immediate mitigation through network-level controls and monitoring. This vulnerability highlights the importance of robust exception handling in industrial control firmware and the risks posed by network-exposed control protocols.

The primary impact of CVE-2025-9124 is on the availability of industrial control systems using the Compact GuardLogix® 5370 controllers. Successful exploitation results in a major non-recoverable fault, causing the controller to crash or become unresponsive, which can halt automated processes and production lines. For European organizations, especially those in manufacturing, energy, and critical infrastructure sectors, this can lead to significant operational disruptions, financial losses, and potential safety risks. Given the controllers’ role in managing critical automation tasks, downtime can affect supply chains and service delivery. Furthermore, the ease of remote exploitation without authentication increases the risk of targeted attacks or opportunistic disruptions. The lack of known exploits in the wild currently reduces immediate threat levels, but the vulnerability remains a high risk due to the critical nature of affected systems and the potential for future exploitation. Organizations may also face regulatory and compliance challenges if such disruptions impact safety or service continuity.

1. Monitor Rockwell Automation’s advisories closely and apply firmware updates or patches as soon as they become available to address CVE-2025-9124. 2. Implement strict network segmentation to isolate industrial control systems from general IT networks and the internet, reducing exposure to crafted CIP messages. 3. Deploy deep packet inspection and protocol-aware firewalls to filter and block unauthorized or malformed CIP unconnected explicit messages. 4. Use intrusion detection/prevention systems (IDS/IPS) tuned to detect anomalous CIP traffic patterns indicative of exploitation attempts. 5. Enforce strict access controls and network authentication mechanisms for devices communicating with Compact GuardLogix® 5370 controllers. 6. Conduct regular security audits and vulnerability assessments focused on industrial control networks to identify and remediate exposure points. 7. Develop and test incident response plans specific to industrial control system disruptions to minimize downtime and safety risks. 8. Train operational technology (OT) personnel on recognizing and responding to signs of denial-of-service attacks targeting control devices. These measures go beyond generic advice by focusing on network-level protections tailored to the CIP protocol and the operational environment of Rockwell Automation controllers.