WordPress File Upload < 4.16.3 - Contributor+ Stored Cross-Site Scripting via Malicious SVG

The plugin allows users with a role as low as Contributor to configure the upload form in a way that allows uploading of SVG files, which could be then be used for Cross-Site Scripting attacks

PoC

1. As a contributor (or above) add the following shortcode to a post: [wordpress_file_upload uploadpatterns=“*.svg”] 2. Preview/view the post and upload the following xss.svg file alert(/XSS/) 3. Go to /wp-content/uploads/xss.svg to trigger the XSS