Routes used to stop running Metasploit tasks (either particular ones or all tasks) allowed GET requests. Only POST requests should have been allowed, as the stop/stop_all routes change the state of the service. This could have allowed an attacker to stop currently-running Metasploit tasks by getting an authenticated user to execute JavaScript. As of Metasploit 4.14.0 (Update 2017061301), the routes for stopping tasks only allow POST requests, which validate the presence of a secret token to prevent CSRF attacks.