CVE-2025-26858 identifies a buffer overflow vulnerability in the Modbus TCP implementation of the Socomec DIRIS Digiware M-70 device, specifically in version 1.6.9. The root cause is improper input validation (CWE-20) of network packets received via the Modbus TCP protocol, which is commonly used for industrial control and energy management systems. An attacker can exploit this vulnerability by sending a sequence of specially crafted, unauthenticated Modbus TCP packets to the device. Due to the buffer overflow, the device’s memory can be corrupted, leading to a denial of service (DoS) condition where the device crashes or becomes unresponsive. The vulnerability has a CVSS v3.1 score of 8.6, reflecting its high severity, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and a scope change (S:C) indicating that the vulnerability impacts components beyond the initially vulnerable one. The impact is limited to availability (A:H), with no direct confidentiality or integrity loss. The vulnerability was published on December 1, 2025, with no known exploits in the wild and no patches currently available. The Socomec DIRIS Digiware M-70 is used primarily in energy monitoring and industrial environments, making this vulnerability particularly relevant to critical infrastructure sectors.

For European organizations, this vulnerability poses a significant risk to the availability of energy monitoring and industrial control systems that rely on the DIRIS Digiware M-70 device. A successful attack could disrupt power management, energy consumption monitoring, or industrial process control, potentially leading to operational downtime, financial losses, and safety risks. Critical infrastructure operators, manufacturing plants, and utilities using these devices could experience service interruptions. Given the unauthenticated and remote nature of the exploit, attackers could launch DoS attacks from outside the network if devices are exposed or insufficiently segmented. This could also affect supply chain reliability and regulatory compliance related to operational continuity and cybersecurity standards in Europe.

1. Immediately implement network segmentation to isolate DIRIS Digiware M-70 devices from general IT networks and restrict Modbus TCP traffic to trusted sources only. 2. Deploy strict firewall rules and access control lists (ACLs) to block unauthorized inbound Modbus TCP packets from untrusted networks, especially the internet. 3. Monitor network traffic for anomalous or malformed Modbus TCP packets that could indicate exploitation attempts. 4. Engage with Socomec support and subscribe to vendor advisories to obtain patches or firmware updates as soon as they become available. 5. Conduct regular vulnerability assessments and penetration testing focused on industrial control systems to identify exposure. 6. Where possible, implement intrusion detection/prevention systems (IDS/IPS) with signatures for Modbus protocol anomalies. 7. Develop and test incident response plans specifically addressing industrial device DoS scenarios to minimize downtime impact.