CVE-2025-41707 identifies a classic buffer overflow vulnerability (CWE-120) in the websocket handler component of the Phoenix Contact QUINT4-UPS/24DC/24DC/5/EIP device. This device is an uninterruptible power supply (UPS) unit used in industrial and critical infrastructure settings. The vulnerability arises from improper handling of input size in websocket messages, allowing an attacker to send a crafted message that overflows a buffer. This overflow leads to a denial of service condition, causing the device to crash or become unresponsive. Notably, the attack vector requires no authentication or user interaction, and the attacker can exploit it remotely over the network. However, the vulnerability does not compromise confidentiality or integrity of data or device operation beyond availability disruption. The CVSS v3.1 base score is 5.3, reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability. No patches or exploits are currently documented, but the vulnerability is publicly disclosed and assigned by CERTVDE. The affected version is identified as VC:00, indicating a specific firmware or hardware revision. The websocket handler is a critical component for remote communication and management, so disruption can impact operational continuity.

For European organizations, especially those in industrial automation, manufacturing, energy, and critical infrastructure sectors, this vulnerability poses a risk of denial of service on power supply units. Such disruptions can lead to unexpected downtime, impacting production lines, data centers, or critical facility operations. While the vulnerability does not allow data theft or device takeover, loss of availability in power management devices can cascade into broader operational failures. Organizations relying on Phoenix Contact QUINT4-UPS devices for uninterrupted power may face service interruptions, potentially affecting safety systems or industrial control processes. The risk is heightened in environments where remote management over websockets is enabled and exposed to untrusted networks. The absence of known exploits reduces immediate threat but does not eliminate risk, especially if attackers develop exploits. The medium severity rating reflects moderate impact with relatively easy exploitation but limited scope to availability only.

1. Implement strict network segmentation to isolate Phoenix Contact QUINT4-UPS devices from untrusted networks, limiting websocket access to trusted management networks only. 2. Employ firewall rules or access control lists (ACLs) to restrict inbound websocket traffic to known, authorized IP addresses. 3. Monitor network traffic for anomalous or malformed websocket messages targeting these devices, using IDS/IPS systems with custom signatures if possible. 4. Disable websocket interfaces if remote management is not required or use VPN tunnels to secure remote access. 5. Engage with Phoenix Contact support to obtain firmware updates or patches once available, and plan timely deployment. 6. Conduct regular vulnerability assessments and penetration testing focusing on industrial control system components to detect similar issues. 7. Maintain incident response plans that include procedures for rapid recovery from UPS device outages to minimize operational impact. 8. Document and audit device configurations to ensure no unnecessary services are exposed externally.