CVE-2025-3511 identifies a vulnerability classified under CWE-1284 (Improper Validation of Specified Quantity in Input) affecting multiple Mitsubishi Electric Corporation products within the CC-Link IE TSN ecosystem, including Remote I/O modules (NZ2GN2S1-32D), Analog-Digital and Digital-Analog Converter modules, FPGA modules, communication LSIs (CP620 and CP610), and MELSEC iQ-R Series modules. The vulnerability arises due to insufficient validation of input data specifying quantities, which can be exploited by an unauthenticated remote attacker sending specially crafted UDP packets to the affected devices. This malformed input causes the devices to enter a denial of service (DoS) state, requiring a manual system reset to restore normal operation. The CVSS v3.1 base score is 7.5 (high), reflecting the network vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but high impact on availability (A:H). The vulnerability affects all versions up to 09 inclusive. The lack of authentication and user interaction requirements combined with remote network accessibility makes exploitation feasible in exposed environments. No patches or known exploits are currently available, but the vulnerability is recognized and enriched by CISA. The affected products are integral components in industrial control systems (ICS) and operational technology (OT) networks, often deployed in manufacturing plants, utilities, and critical infrastructure.

The primary impact of CVE-2025-3511 is a denial of service condition that disrupts the availability of Mitsubishi Electric CC-Link IE TSN modules, which are critical for real-time industrial automation and control processes. For European organizations, particularly those in manufacturing, energy, transportation, and critical infrastructure sectors, this could lead to operational downtime, production halts, and potential safety risks if control systems become unresponsive. The requirement for a system reset to recover means that automated failover or redundancy may be insufficient to maintain continuous operation. Given the widespread use of Mitsubishi Electric products in European industrial environments, this vulnerability could affect supply chains and service delivery. Although confidentiality and integrity are not impacted, the availability disruption alone can have significant economic and safety consequences. The lack of known exploits currently limits immediate risk, but the ease of exploitation and network accessibility elevate the threat level. Organizations with exposed or poorly segmented OT networks are particularly vulnerable to remote attacks leveraging this flaw.

1. Implement strict network segmentation to isolate CC-Link IE TSN devices from general IT networks and the internet, limiting exposure to untrusted sources. 2. Deploy firewall rules and intrusion prevention systems (IPS) to filter and block unsolicited or malformed UDP traffic targeting the affected modules' communication ports. 3. Monitor network traffic for unusual patterns or spikes in UDP packets directed at Mitsubishi devices, enabling early detection of exploitation attempts. 4. Coordinate with Mitsubishi Electric for timely patch releases and apply firmware updates as soon as they become available. 5. Establish robust incident response procedures to quickly reset affected devices and restore operations if a DoS event occurs. 6. Conduct regular security assessments and penetration tests focusing on OT environments to identify and remediate exposure points. 7. Limit physical and network access to critical control modules to authorized personnel only. 8. Maintain up-to-date asset inventories to track affected devices and their firmware versions for targeted mitigation.