diff --git a/src/Composer/Util/GitHub.php b/src/Composer/Util/GitHub.php
index b72eb2575fd7..49db10a360d0 100644
--- a/src/Composer/Util/GitHub.php
+++ b/src/Composer/Util/GitHub.php
@@ -189,7 +189,7 @@ public function getSsoUrl(array $headers)
             return $url;
         }
 
-        return;
+        return null;
     }
 
     /**