WordPress versions 4.4.1 and earlier are affected by two security issues: a possible SSRF for certain local URIs, reported by Ronni Skansing; and an open redirection attack, reported by Shailesh Suthar.
Thank you to both reporters for practicing responsible disclosure.
In addition to the security issues above, WordPress 4.4.2 fixes 17 bugs from 4.4 and 4.4.1. For more information, see the release notes or consult the list of changes.
Download WordPress 4.4.2 or venture over to Dashboard → Updates and simply click “Update Now.” Sites that support automatic background updates are already beginning to update to WordPress 4.4.2.
Thanks to everyone who contributed to 4.4.2:
Andrea Fercia, berengerzyla, Boone Gorges, Chandra Patel, Chris Christoff, Dion Hulse, Dominik Schilling, firebird75, Ivan Kristianto, Jennifer M. Dodd, salvoaranzulla