I also did have the same problem: a new user with admin rights registered as a user [email protected] today and I am trying to restore older backups.
Our service provide did not find any malware or anything in our site. It would be very useful to know if this hack comes from some Trojans in our PC or from a PLUGIN. This is the first time that I see somebody have dare to create its own admin account. This is quite strong security issue.
