diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 32b048e524d6773538918eca175b3f422f9c2aa7..7158d4f8dae4fe2482691e071a1f7751468f6b9a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -814,8 +814,14 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 	u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
 					     tcp_sk(sk)->snd_nxt;
 
+	/* RFC 7323 2.3
+	 * The window field (SEG.WND) of every outgoing segment, with the
+	 * exception of <SYN> segments, MUST be right-shifted by
+	 * Rcv.Wind.Shift bits:
+	 */
 	tcp_v4_send_ack(sock_net(sk), skb, seq,
-			tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
+			tcp_rsk(req)->rcv_nxt,
+			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 			tcp_time_stamp,
 			req->ts_recent,
 			0,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 33df8b8575cceb6f4bf50d9a50ab5a6afa79cd86..94f4f89d73e791ba2ae7bdc7e7ac5bd7bc66a8d4 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -944,9 +944,15 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 	 */
+	/* RFC 7323 2.3
+	 * The window field (SEG.WND) of every outgoing segment, with the
+	 * exception of <SYN> segments, MUST be right-shifted by
+	 * Rcv.Wind.Shift bits:
+	 */
 	tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
-			tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
+			tcp_rsk(req)->rcv_nxt,
+			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 			tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 			0, 0);