--- /dev/null
+From 3ab9291a563656dfebcb7de67c86351541f3de1c Mon Sep 17 00:00:00 2001
+From: Francesco Castellano <francesco.castellano@messagenet.it>
+Date: Fri, 28 Jun 2019 18:15:31 +0200
+Subject: [PATCH] chan_sip: Handle invalid SDP answer to T.38 re-invite
+
+The chan_sip module performs a T.38 re-invite using a single media
+stream of udptl, and expects the SDP answer to be the same.
+
+If an SDP answer is received instead that contains an additional
+media stream with no joint codec a crash will occur as the code
+assumes that at least one joint codec will exist in this
+scenario.
+
+This change removes this assumption.
+
+ASTERISK-28465
+
+Change-Id: I8b02845b53344c6babe867a3f0a5231045c7ac87
+---
+
+diff --git a/channels/chan_sip.c b/channels/chan_sip.c
+index 7c8928d..223ff3c 100644
+--- a/channels/chan_sip.c
++++ b/channels/chan_sip.c
+@@ -10911,7 +10911,13 @@
+ ast_rtp_lookup_mime_multiple2(s3, NULL, newnoncodeccapability, 0, 0));
+ }
+
+- if (portno != -1 || vportno != -1 || tportno != -1) {
++ /* When UDPTL is negotiated it is expected that there are no compatible codecs as audio or
++ * video is not being transported, thus we continue in this function further up if that is
++ * the case. If we receive an SDP answer containing both a UDPTL stream and another media
++ * stream however we need to check again to ensure that there is at least one joint codec
++ * instead of assuming there is one.
++ */
++ if ((portno != -1 || vportno != -1 || tportno != -1) && ast_format_cap_count(newjointcapability)) {
+ /* We are now ready to change the sip session and RTP structures with the offered codecs, since
+ they are acceptable */
+ unsigned int framing;