Lack of input validation/sanitization in the 'setLanCfg' API endpoint in httpd in the Tenda RX2 Pro 16.03.30.14 allows a remote attacker that is authorized to the web management portal to gain root shell access to the device by sending a crafted web request. This is persistent because the command injection is saved in the configuration of the device.
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.