To Do List Member 1.4 - 1.6 - Unauthenticated Stored XSS, File Listing and Deletion via Unprotected Upload Handler

The To Do List Member WordPress plugin from 1.4 through 1.6 ships a file upload endpoint that does not load WordPress and therefore applies no authentication, capability or nonce check of any kind, and validates only the name of an uploaded file rather than its content, allowing unauthenticated users to store active content served from the site's own origin, and to list and delete the files already staged there.