Shared Files < 1.7.70 - Unauthenticated Limited File Upload

The Shared Files WordPress plugin before 1.7.67, shared-files-pro WordPress plugin before 1.7.70 do not perform a capability check in their file-upload handler, which is registered for unauthenticated users and protected only by a nonce that is output on public pages, so an unauthenticated visitor can upload files to a publicly accessible directory and read the server's absolute path from the response. Uploads are limited to WordPress's allowed MIME types, so executable PHP cannot be uploaded.