diff --git a/login/confirm.php b/login/confirm.php
index 6f4d76e3f36..fb85f91d47d 100644
--- a/login/confirm.php
+++ b/login/confirm.php
@@ -25,7 +25,7 @@
  */
 
 require(__DIR__ . '/../config.php');
-require(__DIR__ . '/lib.php');
+require_once(__DIR__ . '/lib.php');
 require_once($CFG->libdir . '/authlib.php');
 
 $data = optional_param('data', '', PARAM_RAW);  // Formatted as:  secret/username