[FrameworkBundle] Checks that the template is readable before checking its modification time

src/Symfony/Bundle/FrameworkBundle/Templating/Loader/FilesystemLoader.php

@@ -65,6 +65,10 @@ class FilesystemLoader implements LoaderInterface
             return false;
         }
 
+        if (!is_readable((string) $storage)) {
+            return false;
+        }
+
         return filemtime((string) $storage) < $time;
     }
 }