diff --git a/userfront/lib/core/services/web_auth_integration_web.dart b/userfront/lib/core/services/web_auth_integration_web.dart
index 9edbfc2f..996a1a26 100644
--- a/userfront/lib/core/services/web_auth_integration_web.dart
+++ b/userfront/lib/core/services/web_auth_integration_web.dart
@@ -55,5 +55,5 @@ bool implIsPopup() {
 
   // Manual parse fallback for cases where Uri.base might miss params due to hash routing
   final search = html.window.location.search;
-  return search.contains('source=adminfront');
+  return search != null && search.contains('source=adminfront');
 }