CVE-2026-84409: high-severity vulnerability in Lantronix G520 Series

The device's update mechanism retrieves metadata for software updates over an unencrypted HTTP connection and stores portions of that metadata for later use. A management interface subsequently returns this stored value in a JSON response, and the web interface responsible for displaying update information inserts that value directly into the page as HTML. This behavior allows attacker‑controlled metadata to be interpreted as script content. In addition, the same authenticated origin provides an interface capable of executing system‑level commands with root privileges. An attacker able to influence update metadata could exploit these conditions to execute arbitrary code within the administrative context of the device.