A command injection vulnerability has been identified in GL.iNet AX1800 router firmware up to version 4.8.3. The vulnerability exists in the remove_rule function within the file /usr/share/gl-ngx/oui-rpc.lua at the RPC Endpoint component. Attackers can exploit this by manipulating the args.id argument to inject arbitrary commands. The attack can be performed remotely without physical access to the device. A public exploit is already available, increasing the risk of active exploitation. The vendor was notified early in the disclosure process. This vulnerability poses a significant threat to users of the affected GL.iNet AX1800 routers running unpatched firmware versions.