CVE-2025-41729 is a vulnerability identified in the Janitza UMG 96-PA, a widely used power quality and energy meter. The vulnerability is classified under CWE-1287, which involves improper validation of the specified type of input. Specifically, the device fails to properly validate the type of Modbus read commands it receives. An unauthenticated remote attacker can exploit this by sending a specially crafted Modbus read command over the network. This malformed command causes the device to enter a denial of service (DoS) state, rendering it unresponsive or causing it to crash. The vulnerability has a CVSS v3.1 base score of 7.5, indicating high severity, with the vector string AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. This means the attack can be launched remotely over the network without any privileges or user interaction, and it impacts availability only, without compromising confidentiality or integrity. The affected product version is listed as 0.0.0, which likely indicates all current versions at the time of disclosure are vulnerable. No patches or fixes have been published yet, and no known exploits are reported in the wild. The vulnerability is particularly concerning for environments where Janitza UMG 96-PA devices are deployed for critical power monitoring and management, as disruption can affect operational continuity and safety. The attack surface is the Modbus protocol interface, commonly used in industrial control systems (ICS) and energy management systems, which often lack robust authentication and encryption. This vulnerability highlights the risks of insufficient input validation in industrial devices communicating over legacy protocols.

The primary impact of CVE-2025-41729 is a denial of service condition on Janitza UMG 96-PA devices, which can disrupt power monitoring and management functions. For European organizations, especially those in energy production, distribution, manufacturing, and critical infrastructure sectors, this can lead to operational downtime, loss of situational awareness, and potential cascading effects on dependent systems. The inability to monitor power quality and consumption accurately can affect energy efficiency, fault detection, and compliance with regulatory standards. In critical infrastructure environments, such as smart grids and industrial plants, this DoS could impair automated control and response mechanisms, increasing the risk of equipment damage or safety incidents. Since the attack requires no authentication and can be launched remotely, the threat actor could be internal or external, including nation-state actors or cybercriminals targeting European energy infrastructure. The lack of confidentiality or integrity impact reduces the risk of data theft or manipulation, but the availability impact alone is significant given the role of these devices. The absence of known exploits currently provides a window for mitigation, but the vulnerability’s simplicity and network accessibility make it a high-priority issue.

1. Implement strict network segmentation to isolate Janitza UMG 96-PA devices from general IT networks and limit access to trusted management systems only. 2. Deploy Modbus protocol-aware intrusion detection/prevention systems (IDS/IPS) to monitor and block malformed or unauthorized Modbus read commands targeting these devices. 3. Use firewall rules to restrict Modbus TCP traffic (typically port 502) to known, authorized IP addresses and block all other sources. 4. Regularly audit and monitor network traffic for unusual Modbus command patterns or spikes in traffic that could indicate exploitation attempts. 5. Engage with Janitza for firmware updates or patches addressing this vulnerability and apply them promptly once available. 6. Consider deploying anomaly detection solutions tailored for industrial control systems to detect deviations in device behavior indicative of DoS conditions. 7. Train operational technology (OT) personnel to recognize signs of device unavailability and have incident response plans specific to power monitoring equipment. 8. If possible, implement redundancy for critical power monitoring devices to maintain availability during an attack or failure. These measures go beyond generic advice by focusing on protocol-specific controls, network architecture, and operational readiness tailored to the affected product and environment.