In Terminalfour 8 through 8.4.1.1, the userLevel parameter in the user management function is not subject to proper server-side authorization checks. A Power User can intercept and modify this parameter to assign the Administrator role to other existing lower-privileged accounts, or invite a new lower-privileged account and escalate its privileges. While manipulating this request, the Power User can also change the target account's password, effectively taking full control of it.