diff --git a/app/site_files.rb b/app/site_files.rb
index 56ce6f92..de5922e6 100644
--- a/app/site_files.rb
+++ b/app/site_files.rb
@@ -191,6 +191,12 @@ get '/site_files/text_editor' do
   dont_browser_cache
 
   @filename = params[:filename]
+
+  if @filename.nil? || @filename.strip.empty?
+    flash[:error] = 'No filename specified.'
+    redirect '/dashboard'
+  end
+
   extname = File.extname @filename
 
   @ace_mode = case extname