WordPress releases two updates to fix multiple threats. There are present risks since version 3.7. If you are WordPress 5.0, update 5.0.1. If you want to stay with WordPress 4, update 4.9.9 version. Updates may be due to backward compatibility issues with any plugins and themes. But having a hack is less difficult.
Hackers allow access to the site, there are seven issues.
Delete the valid file
Authentic post type type
Php object injection through meta data
Verified Cross Site Script (XSS)
The Cross Site Script (XSS) that can affect the plugin
User activating screen search engine indexing
Deletes emails and default passwords to find the engine
Upload file to XSS on Apache Web Servers
Version of the WordPress Infected
These seven risks affect Wordpress, Version 3, 4, and 5. All WordPress users are recommended to upgrade to the WordPress version 4.9.9 or 5.0.1.
Wordpress Version 5.0 and earlier are affected by the following insects, which are fixed in version 5.0.1. The latest versions of WordPress 4.9 and older releases are also available, for users who are not updated 5.0.
The problem of a backward sync is a problem that causes some functions to work more. For example, <form> elements have been disabled to use authors. It can affect the plug-in function as long as they can not update even in the new environment.
Background compatibility issues
Another problem of affecting the latest version of WordPress is unable to upload the CSV files. According to a full-time WordPress partner, it was necessary to disable the upload of CSV files.
A discussion shot CSV files on official WordPress web site are temporarily disabled on WordPress unless a proper bug fixes are created.
Should you upgrade
Yes, you should upgrade quickly. Many WordPress sites are upgraded automatically. If you are not upgrading at 4.9.9 or 5.0.1 at this time, you should start the update update. It's easy to update, just go to your WordPress dashboard and have an announcement.
Yastast SEO 9.1 explained the Vulnerability
Reporting all in a SEO pack
Studies show that web security affects SEO directly
SEO and Cybersecurity: How to SEO Industry Relationship