Microsoft Power Pages Elevation of Privilege Vulnerability

An improper access control vulnerability in Power Pages allows an unauthorized attacker to elevate privileges over a network potentially bypassing the user registration control.
This vulnerability has already been mitigated in the service and all affected customers have been notified. This update addressed the registration control bypass. Affected customers have been given instructions on reviewing their sites for potential exploitation and clean up methods. If you've not been notified this vulnerability does not affect you.