diff --git a/src/plugins/platforms/windows/qwindowsmousehandler.h b/src/plugins/platforms/windows/qwindowsmousehandler.h
index bd36d9f44c..86f18a0482 100644
--- a/src/plugins/platforms/windows/qwindowsmousehandler.h
+++ b/src/plugins/platforms/windows/qwindowsmousehandler.h
@@ -88,9 +88,9 @@ private:
     QPointer<QWindow> m_trackedWindow;
     QHash<DWORD, int> m_touchInputIDToTouchPointID;
     QHash<int, QPointF> m_lastTouchPositions;
-    QTouchDevice *m_touchDevice;
-    bool m_leftButtonDown;
-    QWindow *m_previousCaptureWindow;
+    QTouchDevice *m_touchDevice = nullptr;
+    bool m_leftButtonDown = false;
+    QWindow *m_previousCaptureWindow = nullptr;
 };
 
 Qt::MouseButtons QWindowsMouseHandler::keyStateToMouseButtons(int wParam)