WordPress 4.7.3 is a security release and should be applied immediately.
Things to note
WordPress versions 4.7.2 and earlier are affected by six security issues and we suggest you update your current site to this version. This version also includes 39 maintenance fixes to the 4.7 release series. You can read more by looking at the release notes: https://codex.wordpress.org/Version_4.7.3
If you have not done so already – download the update or simply use your existing installation of WordPress to update your site. Either way – this is an excellent time to make a backup copy of your site(s) before upgrading.