diff --git a/sys/netinet6/in6_pcb.c b/sys/netinet6/in6_pcb.c
--- a/sys/netinet6/in6_pcb.c
+++ b/sys/netinet6/in6_pcb.c
@@ -335,7 +335,7 @@
  */
 static int
 in6_pcbladdr(struct inpcb *inp, struct sockaddr_in6 *sin6,
-    struct in6_addr *plocal_addr6)
+    struct in6_addr *plocal_addr6, bool sas_required)
 {
 	int error = 0;
 	int scope_ambiguous = 0;
@@ -364,13 +364,25 @@
 	if ((error = prison_remote_ip6(inp->inp_cred, &sin6->sin6_addr)) != 0)
 		return (error);
 
-	error = in6_selectsrc_socket(sin6, inp->in6p_outputopts,
-	    inp, inp->inp_cred, scope_ambiguous, &in6a, NULL);
-	if (error)
-		return (error);
+	if (sas_required) {
+		error = in6_selectsrc_socket(sin6, inp->in6p_outputopts,
+		    inp, inp->inp_cred, scope_ambiguous, &in6a, NULL);
+		if (error)
+			return (error);
+	} else {
+		/*
+		 * Source address selection isn't required when syncache
+		 * has already established connection and both source and
+		 * destination addresses was chosen.
+		 *
+		 * This also includes the case when fwd_tag was used to
+		 * select source address in tcp_input().
+		 */
+		in6a = inp->in6p_laddr;
+	}
+
 	if (IN6_IS_ADDR_UNSPECIFIED(&in6a))
 		return (EHOSTUNREACH);
-
 	/*
 	 * Do not update this earlier, in case we return with an error.
 	 *
@@ -398,7 +410,7 @@
  */
 int
 in6_pcbconnect(struct inpcb *inp, struct sockaddr_in6 *sin6, struct ucred *cred,
-    bool rehash __unused)
+    bool sas_required)
 {
 	struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
 	struct sockaddr_in6 laddr6;
@@ -432,7 +444,8 @@
 	 * Call inner routine, to assign local interface address.
 	 * in6_pcbladdr() may automatically fill in sin6_scope_id.
 	 */
-	if ((error = in6_pcbladdr(inp, sin6, &laddr6.sin6_addr)) != 0)
+	if ((error = in6_pcbladdr(inp, sin6, &laddr6.sin6_addr,
+	    sas_required)) != 0)
 		return (error);
 
 	if (in6_pcblookup_hash_locked(pcbinfo, &sin6->sin6_addr,