diff --git a/src/widgets/dialogs/qmessagebox.cpp b/src/widgets/dialogs/qmessagebox.cpp
index 5d0c84e9d4..ca7af90c15 100644
--- a/src/widgets/dialogs/qmessagebox.cpp
+++ b/src/widgets/dialogs/qmessagebox.cpp
@@ -2824,7 +2824,7 @@ bool QMessageBoxPrivate::canBeNativeDialog() const
     if (strcmp(QMessageBox::staticMetaObject.className(), q->metaObject()->className()) != 0)
         return false;
 
-    for (auto *customButton : customButtonList) {
+    for (auto *customButton : buttonBox->buttons()) {
         if (QPushButton *pushButton = qobject_cast<QPushButton *>(customButton)) {
             // We can't support buttons with menus in native dialogs (yet)
             if (pushButton->menu())