diff --git a/app/controller/cron.php b/app/controller/cron.php
index 48a900f4ddd02d0e6b3162f5a4152c63abe791ac..4591c050925c12bf4843fead1d3222aae391f0f8 100644
--- a/app/controller/cron.php
+++ b/app/controller/cron.php
@@ -22,6 +22,9 @@ class Cron extends Controller
     {
         // This method is used to generate a piplome. It might be called with an
         // id parameters, in which case we will ask to regenerate a specific piplome.
+        if (!$f3->exists('SESSION.user')) {
+            $f3->reroute('/login');
+        }
         $logger = new \Log("/piplome.log");
         $ids = array();
         $db = $f3->get('DB');