AuthWP is a MediaWiki extension that allows authentication with WordPress credentials. It is a rewrite of WPMW by Ciaran Gultnieks and is intended to provide essentially the same functionality using SessionManager and AuthenticationProvider introduced in MediaWiki 1.27. In particular:

• A valid WordPress session allows access to MediaWiki. Authenticating to MediaWiki with WordPress credentials signs the user in to WordPress.
• Logging out from MediaWiki also logs the user out from WordPress and vice versa.
• User passwords are maintained in WordPress only, but can be changed from either MediaWiki or WordPress. MediaWiki users without corresponding WordPress accounts will have their passwords maintained by MediaWiki.
• MediaWiki can be configured to auto-create accounts for existing WordPress users when they first access the wiki. Generally, user management will have to be done from WordPress, but because MediaWiki requires a different set of attributes for its users (e.g. group membership and number of edits), it is not possible to do away with the MediaWiki accounts entirely.
• It is also possible to simultaneously create accounts in WordPress when users register for the wiki. Because this will use WordPress default values for all user attributes not supplied during the MediaWiki registration process, users may end up with e.g. empty email addresses. This is a potential problem because WordPress assumes email addresses are unique user identifiers.

See the MediaWiki Extension page for further documentation.