diff --git a/src/Control/SAMLController.php b/src/Control/SAMLController.php
index e53dc52..cc280ee 100644
--- a/src/Control/SAMLController.php
+++ b/src/Control/SAMLController.php
@@ -162,6 +162,8 @@ public function acs()
             $attributes['GUID'][0] = $guid;
         }
 
+        $this->extend('updateAttributes', $attributes);
+
         $fieldToClaimMap = array_flip(Member::config()->claims_field_mappings);
 
         // Write a rudimentary member with basic fields on every login, so that we at least have something