WordPress 4.3.1 is now available and should be applied to all your sites as soon as possible as is a security release that addresses two cross-site scripting vulnerabilities and a potential privilege escalation. For more information, see the release notes or view the list of changes.
You can read more about the update: https://wordpress.org/news/2015/09/wordpress-4-3-1/
You can download WordPress 4.3.1: http://wordpress.org/wordpress-4.3.1.zip
WordPress 4.3 is now available for download.
For WordPress Users
This update includes a number of improvements in the admin area (menu customizer, formatting shortcuts, site icons), automatically generated secure passwords for new users, comments turned off by default for pages, and other great changes which will make working with WordPress on all your devices easier and more enjoyable.
For WordPress Developers
There are some noticeable changes with this new version as well including a new page template (singular.php), multisite changes, list table changes, and other customizer enhancements.
You can read more about the update: http://wordpress.org/wordpress-4.3.zip