The FreePBX Endpoint Manager module includes a Network Scanning feature that provides web-based access to nmap functionality for network device discovery. In Endpoint Manager 16 before 16.0.92 and 17 before 17.0.6, insufficiently sanitized user-supplied input allows authenticated OS command execution as the asterisk user. Authentication with a known username is required. Updating to Endpoint Manager 16.0.92 or 17.0.6 addresses the issue.