An OS command injection vulnerability exists in the OptiLink ONT1GEW GPON router firmware version V2.1.11_X101 Build 1127.190306 and earlier. The router’s web management interface fails to properly sanitize user input in the target_addr parameter of the formTracert and formPing administrative endpoints. An authenticated attacker can inject arbitrary operating system commands, which are executed with root privileges, leading to remote code execution. Successful exploitation enables full compromise of the device.