On April 20, 2015, WordPress 4.0.2 was released to the public. This is a security update for all previous WordPress versions.
To download WordPress 4.0.2, update automatically from the Dashboard > Updates menu in your site's admin area or visit https://wordpress.org/download/release-archive/.
For step-by-step instructions on installing and updating WordPress:
If you are new to WordPress, we recommend that you begin with the following:
From the announcement post:
license.txt readme.html wp-admin/includes/class-wp-comments-list-table.php wp-admin/includes/dashboard.php wp-admin/includes/post.php wp-admin/includes/template.php wp-admin/js/nav-menu.js wp-includes/capabilities.php wp-includes/class-wp-editor.php wp-includes/formatting.php wp-includes/js/plupload/plupload.flash.swf wp-includes/version.php wp-includes/wp-db.php