An issue was discovered on Tenda AC7 devices with firmware through V15.03.06.44_CN(AC7), AC9 devices with firmware through V15.03.05.19(6318)_CN(AC9), and AC10 devices with firmware through V15.03.06.23_CN(AC10). A command Injection vulnerability allows attackers to execute arbitrary OS commands via a crafted goform/setUsbUnload request. This occurs because the "formsetUsbUnload" function executes a dosystemCmd function with untrusted input.
https://blog.xlab.qianxin.com/catddos-derivative-en/
https://github.com/zsjevilhex/iot/blob/master/route/tenda/tenda-01/Tenda.md