diff --git a/core/modules/file/src/Controller/FileWidgetAjaxController.php b/core/modules/file/src/Controller/FileWidgetAjaxController.php
index 90176f8..08b35fc 100644
--- a/core/modules/file/src/Controller/FileWidgetAjaxController.php
+++ b/core/modules/file/src/Controller/FileWidgetAjaxController.php
@@ -31,10 +31,9 @@ class FileWidgetAjaxController extends FormAjaxController {
    */
   public function upload(Request $request) {
     $form_parents = explode('/', $request->query->get('element_parents'));
-    $form_build_id = $request->query->get('form_build_id');
     $request_form_build_id = $request->request->get('form_build_id');
 
-    if (empty($request_form_build_id) || $form_build_id !== $request_form_build_id) {
+    if (empty($request_form_build_id)) {
       // Invalid request.
       drupal_set_message(t('An unrecoverable error occurred. The uploaded file likely exceeded the maximum file size (@size) that this server supports.', array('@size' => format_size(file_upload_max_size()))), 'error');
       $response = new AjaxResponse();