Tenda AC6 router firmware 15.03.05.19 contains a command injection vulnerability in the formSetIptv function, which processes requests to the /goform/SetIPTVCfg web interface. When handling the list and vlanId parameters, the sub_ADBC0 helper function concatenates these user-supplied values into nvram set system commands using doSystemCmd, without validating or sanitizing special characters (e.g., ;, ", #). An unauthenticated or authenticated attacker can exploit this by submitting a crafted POST request, leading to arbitrary system command execution on the affected device.