diff --git a/core/lib/Drupal/Core/Database/Query/Update.php b/core/lib/Drupal/Core/Database/Query/Update.php
index abbbc2b49e6812e5d9074a30c36f5e66ca83b078..92f69d4bc3c93671d02842f5a4568bdc42beafbb 100644
--- a/core/lib/Drupal/Core/Database/Query/Update.php
+++ b/core/lib/Drupal/Core/Database/Query/Update.php
@@ -222,7 +222,7 @@ public function execute() {
     // Because we filter $fields the same way here and in __toString(), the
     // placeholders will all match up properly.
     $max_placeholder = 0;
-    foreach ($fields as $field => $value) {
+    foreach ($fields as $value) {
       $update_values[':db_update_placeholder_' . ($max_placeholder++)] = $value;
     }