CVE-2025-9161 is a high-severity vulnerability affecting Rockwell Automation's FactoryTalk Optix product, specifically versions 1.5.0 through 1.5.7. The vulnerability stems from improper neutralization of special elements used in commands (CWE-77), manifesting as a command injection flaw within the FactoryTalk Optix MQTT broker component. The root cause is the lack of URI sanitization, which allows an attacker to load remote Mosquitto plugins maliciously. This capability can be leveraged to achieve remote code execution (RCE) on the affected system. The vulnerability requires low privileges (PR:L), partial authentication (AT:P), and user interaction (UI:A), but the attack vector is network-based (AV:N), meaning exploitation can occur remotely over the network. The impact on confidentiality, integrity, and availability is high, as successful exploitation could allow an attacker to execute arbitrary code, potentially leading to full system compromise, data theft, or disruption of industrial control processes. No known exploits are currently reported in the wild, and no patches have been published yet. The CVSS 4.0 score is 7.3, reflecting the significant risk posed by this vulnerability. FactoryTalk Optix is an industrial automation software suite used for monitoring and controlling manufacturing processes, making this vulnerability particularly critical in operational technology (OT) environments where safety and uptime are paramount.

For European organizations, especially those in manufacturing, energy, utilities, and critical infrastructure sectors, this vulnerability poses a substantial risk. FactoryTalk Optix is widely used in industrial automation, and a successful remote code execution attack could lead to operational disruptions, safety incidents, and potential data breaches. The ability to load remote plugins remotely could allow attackers to implant persistent malware or disrupt control systems, causing production downtime or physical damage. Given the interconnected nature of industrial control systems in Europe and the increasing adoption of Industry 4.0 technologies, exploitation of this vulnerability could have cascading effects across supply chains and critical services. Additionally, regulatory frameworks such as the NIS Directive and GDPR impose strict requirements on cybersecurity and incident reporting, increasing the legal and financial consequences of a breach. The requirement for user interaction and partial authentication may limit some attack scenarios but does not eliminate the risk, especially in environments where insider threats or phishing attacks are possible.

European organizations should implement a multi-layered mitigation strategy beyond generic patching advice. First, they should immediately audit and restrict network access to FactoryTalk Optix MQTT brokers, limiting exposure to trusted internal networks and employing network segmentation to isolate OT environments from IT networks. Deploy strict firewall rules and intrusion detection/prevention systems (IDS/IPS) tuned to detect anomalous MQTT traffic or attempts to load unauthorized plugins. Implement robust authentication and authorization controls, ensuring that only authorized users and systems can interact with the MQTT broker. Conduct user awareness training to reduce the risk of social engineering attacks that could facilitate user interaction requirements. Monitor logs and network traffic for unusual activity indicative of exploitation attempts. Since no patches are currently available, consider deploying application-layer proxies or web application firewalls (WAFs) capable of sanitizing or blocking malicious URI requests targeting the MQTT broker. Engage with Rockwell Automation for updates and apply patches promptly once released. Finally, develop and test incident response plans tailored to OT environments to quickly contain and remediate any compromise.