diff --git a/sys/dev/if_wg/module/if_wg_session.c b/sys/dev/if_wg/module/if_wg_session.c
index 492f356bca9..13ad2ea5c9f 100644
--- a/sys/dev/if_wg/module/if_wg_session.c
+++ b/sys/dev/if_wg/module/if_wg_session.c
@@ -1859,6 +1859,40 @@ wg_index_drop(struct wg_softc *sc, uint32_t key0)
 	SLIST_INSERT_HEAD(&peer->p_unused_index, iter, i_unused_entry);
 }
 
+static int
+wg_update_endpoint_addrs(struct wg_endpoint *e, const struct sockaddr *srcsa,
+    struct ifnet *rcvif)
+{
+	const struct sockaddr_in *sa4;
+	const struct sockaddr_in6 *sa6;
+	int ret = 0;
+
+	/*
+	 * UDP passes a 2-element sockaddr array: first element is the
+	 * source addr/port, second the destination addr/port.
+	 */
+	if (srcsa->sa_family == AF_INET) {
+		sa4 = (const struct sockaddr_in *)srcsa;
+		e->e_remote.r_sin = sa4[0];
+		/* Only update dest if not mcast/bcast */
+		if (!(IN_MULTICAST(ntohl(sa4[1].sin_addr.s_addr)) ||
+		      sa4[1].sin_addr.s_addr == INADDR_BROADCAST ||
+		      in_broadcast(sa4[1].sin_addr, rcvif))) {
+			e->e_local.l_in = sa4[1].sin_addr;
+		}
+	} else if (srcsa->sa_family == AF_INET6) {
+		sa6 = (const struct sockaddr_in6 *)srcsa;
+		e->e_remote.r_sin6 = sa6[0];
+		/* Only update dest if not multicast */
+		if (!IN6_IS_ADDR_MULTICAST(&sa6[1].sin6_addr))
+			e->e_local.l_in6 = sa6[1].sin6_addr;
+	} else {
+		ret = EAFNOSUPPORT;
+	}
+
+	return (ret);
+}
+
 static void
 wg_input(struct mbuf *m0, int offset, struct inpcb *inpcb,
 		 const struct sockaddr *srcsa, void *_sc)
@@ -1890,12 +1924,11 @@ wg_input(struct mbuf *m0, int offset, struct inpcb *inpcb,
 		goto free;
 	}
 	e = wg_mbuf_endpoint_get(m);
-	if (srcsa->sa_family == AF_INET)
-		e->e_remote.r_sin = *(const struct sockaddr_in *)srcsa;
-	else if (srcsa->sa_family == AF_INET6)
-		e->e_remote.r_sin6 = *(const struct sockaddr_in6 *)srcsa;
-	else
-		e->e_remote.r_sa = *srcsa;
+
+	if (wg_update_endpoint_addrs(e, srcsa, m->m_pkthdr.rcvif)) {
+		DPRINTF(sc, "unknown family\n");
+		goto free;
+	}
 	verify_endpoint(m);
 
 	if_inc_counter(sc->sc_ifp, IFCOUNTER_IPACKETS, 1);