WordPress 4.2.2 is now available. This is a critical security release for all previous versions and we strongly encourage you to update your sites immediately. Contact us if you require any assistance*.
Version 4.2.2 addresses two security issues:
The Genericons icon font package, which is used in a number of popular themes and plugins, contained an HTML file vulnerable to a cross-site scripting attack. All affected themes and plugins hosted on WordPress.org (including the Twenty Fifteen default theme) have been updated today by the WordPress security team to address this issue by removing this nonessential file. To help protect other Genericons usage, WordPress 4.2.2 proactively scans the wp-content directory for this HTML file and removes it.
WordPress versions 4.2 and earlier are affected by a critical cross-site scripting vulnerability, which could enable anonymous users to compromise a site. WordPress 4.2.2 includes a comprehensive fix for this issue.