CVE-2018-14028

In WordPress 4.9.7, plugins uploaded via the admin area are not verified as
being ZIP files. This allows for PHP files to be uploaded. Once a PHP file
is uploaded, the plugin extraction fails, but the PHP file remains in a
predictable wp-content/uploads location, allowing for an attacker to then
execute the file. This represents a security risk in limited scenarios
where an attacker (who does have the required capabilities for plugin
uploads) cannot simply place arbitrary PHP code into a valid plugin ZIP
file and upload that plugin, because a machine’s wp-content/plugins
directory permissions were set up to block all new plugins.