Once in a while, someone comes along and claims that Brim is not secure. It is easy to embed iframes or javascript calls that make the browser go to a different page, the application becomes unuseable untill the problematic item is removed from the database.
This claim is valid, you can easily install those kind of 'malicious' descriptions etc. The question however is; would you do this in your own account?
Note that the demo account is a normal account, except for the fact that the language and theme are reset after each login. This means that a demo user can do anything else a normal user can do as well, including adding scripts in description fields etc. This has nothing to do with security, the test user is in a trusted environment, like any other user, right after login.
Brim is a secure application, passwords are stored in hash (MD5 algorithm) in the database, the password itself is not stored. XSS on the login screen is not possible (until someone proves me otherwise). Once you login, you can add javascript and iframes in the different fields of the presented items, but this has become the users responsibility. Besides that, this does not cripple the application itself, all that can be done is reroute the browser elsewhere.