An unauthenticated OS command injection vulnerability exists in the Shenzhen Aitemi M300 Wi-Fi Repeater (hardware model MT02). When configuring the device in Extender mode via its captive portal, the extap2g SSID field is inserted unescaped into a reboot-time shell script. This allows remote attackers within Wi-Fi range to inject arbitrary shell commands that execute as root during device reboot, leading to full system compromise.