An authenticated OS command injection vulnerability exists in various D-Link routers (tested on DIR-615H1 running firmware version 8.04) via the tools_vct.htm endpoint. The web interface fails to sanitize input passed from the ping_ipaddr parameter to the tools_vct.htm diagnostic interface, allowing attackers to inject arbitrary shell commands using backtick encapsulation. With default credentials, an attacker can exploit this blind injection vector to execute arbitrary commands.