If you are seeing a login box, you are likely running Selenium Grid in a specific configuration or with a third-party wrapper (like Selenoid or a Docker container maintained by a specific vendor).

However, later that day, John encountered another engineer, Emily, who was setting up a similar grid on a different part of their infrastructure. She mentioned she was using an older version of Selenium Grid and was having trouble with the web UI, complaining about not being able to log in.

By default, Selenium Grid (versions 3 and 4) does enable any authentication. If you expose a Grid hub/node/router to a network without configuring security, anyone who can reach it can run commands on your infrastructure.