The JSST and the Joomla! Security Center report:
[20161001] - Core - Account Creation
Inadequate checks allows for users to register on a site when
registration has been disabled.
[20161002] - Core - Elevated Privilege
Incorrect use of unfiltered data allows for users to register on a
site with elevated privileges.
[20161003] - Core - Account Modifications
Incorrect use of unfiltered data allows for existing user accounts
to be modified; to include resetting their username, password, and
user group assignments.