I am not sure if there is another thread about this on here but am posting to raise awareness.
A number of posters have been able to log in to other posters accounts. When entering their own username and password, it has allowed access to another posters private account including their name change history, private messages etc.
I was sceptical so logged out of my own and logged back in, sure enough it put me into someone elses account. I posted as that person as evidence then logged out. It has now allowed me back into my own account.
MN do not seem to be addressing the problem so if you could report it to them, or go on to the thread in 'site stuff' and post there, they might take it seriously. Anyone can have access to your account right now and unless the poster personally PM's you and alerts you to it, you would have no idea. Very worrying.