diff --git a/app/config/routing.yml b/app/config/routing.yml
index 684d3649d9..6c3a990140 100644
--- a/app/config/routing.yml
+++ b/app/config/routing.yml
@@ -1,4 +1,8 @@
 # Internal routing configuration to handle ESI
+# ****** WARNING ******
+# This route should be enabled with caution as it can open a security vulnerability
+# see http://symfony.com/blog/security-release-symfony-2-0-20-and-2-1-5-released for more information
+# ****** WARNING ******
 #_internal:
 #    resource: "@FrameworkBundle/Resources/config/routing/internal.xml"
 #    prefix:   /_internal