A User with "Create Survey" access only was testing LimeSurvey to see how prone it is to javascript vulnerabilities and edited their account name to include a <script> tag. Attached is what they entered and now when I try to edit/delete/add any usernames, I received the message below:

"Access denied!

Security alert: Someone may be trying to use your LimeSurvey session (CSRF attack suspected). If you just clicked on a malicious link, please report this to your system administrator.
Also this problem can occur when you are working/editing in LimeSurvey in several browser windows/tabs at the same time."

Now as a Super Admin I cannot make changes to Create/Edit user page.