--- channels/chan_sip.c	(revision 397709)
+++ channels/chan_sip.c	(revision 397710)
@@ -26004,7 +26004,7 @@
 			p->invitestate = INV_TERMINATED;
 			p->pendinginvite = 0;
 			acked = __sip_ack(p, seqno, 1 /* response */, 0);
-			if (find_sdp(req)) {
+			if (p->owner && find_sdp(req)) {
 				if (process_sdp(p, req, SDP_T38_NONE)) {
 					return -1;
 				}
