Content complements of: https://wordpress.org/news/2015/09/wordpress-4-3-1/
WordPress 4.3.1 is now available. This is a security release for all previous versions and we strongly encourage you to update your sites immediately.
This release addresses three issues, including two cross-site scripting vulnerabilities and a potential privilege escalation.
WordPress versions 4.3 and earlier are vulnerable to a cross-site scripting vulnerability when processing shortcode tags (CVE-2015-5714). Reported by Shahar Tal and Netanel Rubin of Check Point.
A separate cross-site scripting vulnerability was found in the user list table. Reported by Ben Bidner of the WordPress security team.
Finally, in certain cases, users without proper permissions could publish private posts and make them sticky (CVE-2015-5715). Reported by Shahar Tal and Netanel Rubin of Check Point.
Our thanks to those who have practiced responsible disclosure of security issues.
WordPress 4.3.1 also fixes twenty-six bugs. For more information, see the release notes or consult the list of changes.
Download WordPress 4.3.1 or venture over to Dashboard → Updates and simply click “Update Now.” Sites that support automatic background updates are already beginning to update to WordPress 4.3.1.
Thanks to everyone who contributed to 4.3.1:
Adam Silverstein, Andrea Fercia, Andrew Ozz, Boone Gorges, Brandon Kraft, chriscct7, Daisuke Takahashi, Dion Hulse, Dominik Schilling, Drew Jaynes, dustinbolton, Gary Pendergast, hauvong, James Huff, Jeremy Felt, jobst, Marin Atanasov, Nick Halsey, nikeo, Nikolay Bachiyski, Pascal Birchler, Paul Ryan, Peter Wilson, Robert Chapin, Samuel Wood, Scott Taylor, Sergey Biryukov, tmatsuur, Tracy Levesque, Umesh Nevase, vortfu, welcher, Weston Ruter