diff --git a/src/core/tcp_out.c b/src/core/tcp_out.c
index ec42164..f595ef8 100644
--- a/src/core/tcp_out.c
+++ b/src/core/tcp_out.c
@@ -1141,7 +1141,7 @@ tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb)
   if (seg->flags & TF_SEG_OPTS_WND_SCALE) {
     /* The Window field in a SYN segment itself (the only type where we send
        the window scale option) is never scaled. */
-    seg->tcphdr->wnd = htons(pcb->rcv_ann_wnd);
+    seg->tcphdr->wnd = htons(LWIP_MIN(pcb->rcv_ann_wnd, 65535U));
   } else
 #endif /* LWIP_WND_SCALE */
   {