Unauthenticated attackers can trigger a persistent Denial of Service condition on HMS Networks Ewon Flexy and Cosy+ industrial gateways by sending specially crafted HTTP requests to the device GUI.

This vulnerability involves a lack of input validation within the device GUI, allowing an unauthenticated remote attacker to cause a system reboot through a crafted HTTP request.

The ability for an unauthenticated actor to force a device reboot directly impacts operational continuity in industrial environments. Given the CVSS score of 7.5, the vulnerability is classified as High severity because it allows for easy, repeatable disruption of critical remote connectivity gateways without requiring prior system access or user credentials.

Immediate Action: Update all affected Ewon Flexy and Cosy+ firmware to the versions specified by the vendor as containing the fix (15.0s4, 22.1s6, or 23.0s3 respectively).

Proactive Monitoring: Monitor network traffic for anomalous HTTP requests directed at the GUI of industrial gateways and review system logs for frequent, unauthorized reboot events.

Compensating Controls: Restrict network access to the device GUI to authorized management subnets only via firewall rules to prevent unauthenticated remote access.

Public Exploit Available: No.

This vulnerability poses a significant risk to the availability of industrial remote access infrastructure. Administrators should prioritize the deployment of the vendor provided firmware updates to eliminate the potential for unauthorized reboots and ensure the stability of the industrial control environment.