Index: sys/netinet/tcp_input.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/netinet/tcp_input.c,v
retrieving revision 1.368
diff -u -p -u -p -r1.368 tcp_input.c
--- sys/netinet/tcp_input.c	16 Apr 2021 12:08:25 -0000	1.368
+++ sys/netinet/tcp_input.c	6 Aug 2021 13:41:35 -0000
@@ -966,6 +966,8 @@ findpcb:
 					tp->t_pmtud_mss_acked = acked;
 
 				tp->snd_una = th->th_ack;
+				/* Pull snd_wl2 up to prevent seq wrap. */
+				tp->snd_wl2 = th->th_ack;
 				/*
 				 * We want snd_last to track snd_una so
 				 * as to avoid sequence wraparound problems
@@ -1015,6 +1017,10 @@ findpcb:
 				tcp_clean_sackreport(tp);
 			tcpstat_inc(tcps_preddat);
 			tp->rcv_nxt += tlen;
+			/* Pull snd_wl1 and rcv_up up to prevent seq wrap. */
+			tp->snd_wl1 = th->th_seq;
+			if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
+				tp->rcv_up = tp->rcv_nxt;
 			tcpstat_pkt(tcps_rcvpack, tcps_rcvbyte, tlen);
 			ND6_HINT(tp);