Index: sys/netinet/tcp_reass.c
===================================================================
--- sys/netinet/tcp_reass.c
+++ sys/netinet/tcp_reass.c
@@ -978,6 +978,20 @@
 			return (0);
 		}
 	}
+	if (th->th_seq == tp->rcv_nxt && TCPS_HAVEESTABLISHED(tp->t_state)) {
+		tp->rcv_nxt += *tlenp;
+		flags = th->th_flags & TH_FIN;
+		TCPSTAT_INC(tcps_rcvoopack);
+		TCPSTAT_ADD(tcps_rcvoobyte, *tlenp);
+		SOCKBUF_LOCK(&so->so_rcv);
+		if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
+			m_freem(m);
+		} else {
+			sbappendstream_locked(&so->so_rcv, m, 0);
+		}
+		sorwakeup_locked(so);
+		return (flags);
+	}
 	/*
 	 * Allocate a new queue entry. If we can't, or hit the zone limit
 	 * just drop the pkt.