require uploaded file's name to match in any case

app/controllers/concerns/uploads_actions.rb

@@ -31,13 +31,17 @@ module UploadsActions
 
     disposition = uploader.image_or_video? ? 'inline' : 'attachment'
 
+    if uploader.filename == params[:filename]
+      return send_upload(uploader, attachment: uploader.filename, disposition: disposition)
+    end
+
     uploader_version = uploader.versions.values.find { |version| version.filename == params[:filename] }
 
     if uploader_version
       return send_upload(uploader_version, attachment: uploader_version.filename, disposition: disposition)
     end
 
-    return send_upload(uploader, attachment: uploader.filename, disposition: disposition)
+    render_404
   end
 
   private