CVE-2025-3511 identifies a vulnerability classified under CWE-1284 (Improper Validation of Specified Quantity in Input) in several Mitsubishi Electric CC-Link IE TSN modules, including Remote I/O module NZ2GN2S1-32D and other related modules. The vulnerability arises because the affected products do not properly validate the quantity field in input data received via UDP packets. This flaw enables a remote attacker to craft malicious UDP packets that trigger a denial of service condition by causing the affected device to reset or become unresponsive. Since the attack vector is network-based (UDP) and requires no authentication or user interaction, it is relatively easy to exploit in environments where these devices are exposed or insufficiently protected. The impact is limited to availability, as the attack does not compromise confidentiality or integrity of data. Recovery from the DoS condition requires a manual or automated system reset of the affected device. The vulnerability affects firmware versions 09 and prior, and no patches have been linked yet, indicating that mitigation currently relies on network-level controls. The affected products are integral components in industrial automation and control systems, particularly in manufacturing environments that use CC-Link IE TSN technology for real-time communication and control. The vulnerability was published on April 25, 2025, with a CVSS v3.1 score of 7.5, reflecting high severity due to ease of exploitation and significant impact on availability.

For European organizations, especially those in manufacturing, energy, and critical infrastructure sectors, this vulnerability poses a significant risk to operational continuity. Mitsubishi Electric’s CC-Link IE TSN modules are widely deployed in industrial automation systems across Europe, where real-time control and communication are essential. A successful exploitation could lead to unexpected device resets, causing production downtime, loss of process control, and potential safety hazards. The denial of service could disrupt supply chains and critical services, leading to financial losses and reputational damage. Since the attack requires no authentication and can be launched remotely via UDP, any exposure of these devices to untrusted networks or insufficiently segmented industrial networks increases risk. The lack of confidentiality and integrity impact means data theft or manipulation is not a direct concern, but availability disruption in industrial control systems can have cascading effects on safety and compliance with regulatory requirements such as NIS2. The absence of known exploits in the wild provides a limited window for proactive mitigation before potential attackers develop weaponized payloads.

1. Immediately implement network segmentation to isolate CC-Link IE TSN devices from general IT and internet-facing networks. 2. Deploy strict firewall rules to block or restrict UDP traffic to and from the affected modules, allowing only trusted management and control systems. 3. Monitor network traffic for anomalous UDP packets targeting these devices, using intrusion detection/prevention systems tuned for industrial protocols. 4. Coordinate with Mitsubishi Electric for firmware updates or patches and plan timely deployment once available. 5. Establish automated or manual procedures for rapid device reset and recovery to minimize downtime if a DoS event occurs. 6. Conduct regular vulnerability assessments and penetration testing focused on industrial control systems to identify exposure. 7. Train operational technology (OT) staff on recognizing and responding to DoS conditions related to this vulnerability. 8. Review and enhance incident response plans to include scenarios involving industrial device availability disruptions. 9. Limit physical and logical access to affected devices to prevent lateral movement by attackers. 10. Collaborate with industry information sharing groups to stay informed about emerging threats and mitigation strategies related to CC-Link IE TSN products.