diff --git a/gdk/broadway/gdkbroadway-server.c b/gdk/broadway/gdkbroadway-server.c
index a2f9e00e84..803152a790 100644
--- a/gdk/broadway/gdkbroadway-server.c
+++ b/gdk/broadway/gdkbroadway-server.c
@@ -598,6 +598,9 @@ _gdk_broadway_server_window_update (GdkBroadwayServer *server,
   BroadwayRequestUpdate msg;
   BroadwayShmSurfaceData *data;
 
+  if (surface == NULL)
+    return;
+
   data = cairo_surface_get_user_data (surface, &gdk_broadway_shm_cairo_key);
   g_assert (data != NULL);