vantage6 is an open-source infrastructure for privacy preserving analysis. Versions prior to 5.0.0 provide an initial user with username "root" and password "root". This is not ideal because attackers know that almost all vantage6 servers have a user with username "root" that probably has admin rights, and the initial password is very weak and it is possible that administrators forget to reset it. Version 5.0.0 fixes the issue. As a workaround, it is possible to delete the "root" user after it has been used to create other users.