Its developers Automattic they just released the new WordPress 4.5.3 update. It is a security update and fixes 17 bugs. 
Let's look at some of the release notes:
WordPress version 4.5.2 and all previous ones are affected by various themeτα ασφάλειας: παρακάμψεις στο redirect στην προσαρμογή, που αναφέρθηκε από τον Yassine Aboukir, δύο διαφορετικά προβλήματα XSS μέσω των ονομάτων των attachments που αναφέρθηκαν από τον Jouko Pynnönen και τον Divyesh Prajapati το ιστορικό των revisions αποκαλύπτει πληροφορίες, αναφέρθηκε ανεξάρτητα από τον John Blackbourn, από την ομάδα ασφαλείας του WordPress και από τον Dan Moen.
A denial of service problem via oEmbed reported by Jennifer Dodd and Automattic, unauthorized category removal from a post reported by David Herrera of Alley Interactive, password change through stolen cookies, reported by Michael Adams from the security team thw WordPress, and some minor vulnerabilities such as the Sanitize_file_name case reported by Peter Westwood of the WordPress Security Team.
More at the following link:
The files that were changed with the update in WordPress 4.5.3 are the following:
readme.html wp-admin/about.php wp-admin/nav-menus.php wp-admin/includes/ajax-actions.php wp-admin/includes/upgrade.php wp-admin/includes/post.php wp- admin/includes/class-wp-media-list-table.php wp-admin/options.php wp-admin/revision.php wp-includes/load.php wp-includes/default-filters.php wp-includes/theme-compat/embed-content.php wp-includes/embed.php wp-includes/class-wp-customize-manager.php wp-includes/js/media-views.js wp-includes/js/tinymce/wp-tinymce.js.gz wp-includes/js/tinymce/plugins/wordpress/plugin.js wp-includes/js/tinymce/plugins/wordpress/plugin.min.js wp-includes/js/tinymce/plugins/wplink/plugin.js wp-includes/js/tinymce/plugins/wplink/plugin.min.js wp-includes/js/media-views.min.js wp-includes/js/jQuery/jquery-migrate.js wp-includes/js/jquery/jquery.js wp-includes/js/jquery/jquery-migrate.min.js wp-includes/class-oembed.php wp-includes/version.php wp-includes/customize/class-wp-customize-media-control.php wp-includes/customize/class-wp-customize-site-icon-control.php wp-includes/pluggable.php wp-includes/script-loader.php wp-includes/formatting.php wp-includes/class-wp-customize-widgets.php wp-includes/post-template.php
