The WordPress File Upload Free and Pro WordPress plugins before 4.16.3 allow users with a role as low as Contributor to perform path traversal via a shortcode argument, which can then be used to upload a PHP code disguised as an image inside the auto-loaded directory of the plugin, resulting in arbitrary code execution.
https://wpscan.com/vulnerability/7a95b3f2-285e-40e3-aead-41932c207623