WordPress 4.2.4 is now available and should be applied to all your sites as soon as possible as it addresses six issues, including three cross-site scripting vulnerabilities and a potential SQL injection that could be used to compromise a site. For more information, see the release notes or view the list of changes.

You can read more about the update: https://wordpress.org/news/2015/08/wordpress-4-2-4-security-and-maintenance-release/

You can download WordPress 4.2.4: http://wordpress.org/wordpress-4.2.4.zip