WordPress 4.2.2 has just been released which contains several important security fixes. We recommend you update immediately if you haven’t already. If you are on one of our WordPress Care & Support Packages, no worries, we have taken care of it for you already! That’s what you pay for. 🙂
This update is important because 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.
The release also includes hardening for a potential cross-site scripting vulnerability when using the visual editor.
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.
The release also fixes 13 other bugs which you can learn more about on the release notes page for 4.2.2.