diff --git a/modules/saml/lib/IdP/SQLNameID.php b/modules/saml/lib/IdP/SQLNameID.php
index 3d2ed767b568bbeb3c136580962288eea8d4d8eb..6a2e6d31f278c0f8bc82b856d0c0b3250e6eb339 100644
--- a/modules/saml/lib/IdP/SQLNameID.php
+++ b/modules/saml/lib/IdP/SQLNameID.php
@@ -282,7 +282,9 @@ class SQLNameID
 
         $res = [];
         while (($row = $query->fetch(PDO::FETCH_ASSOC)) !== false) {
-            $res[$row['_user']] = $row['_value'];
+            $user = strval($row['_user']);
+            $value = strval($row['_value']);
+            $res[$user] = $value;
         }
 
         return $res;