Change Password

I believe you mean that once you're logged in, you can edit your user account. You can indeed type any user name you like. If the user name us not in use, you are in fact changing your own user name (and perhaps your password). You are not changing the password of someone else. If you type a username of an existing user, you get an error message.
Please provide more information if I understood you incorrectly and you still believe there is a security issue with the passwords.
- not reproducible
- need more info

nonisue hence closed