diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 3dbfb3fe81..ebec59f26d 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -4547,10 +4547,10 @@ static struct ast_frame *sip_rtp_read(struct ast_channel *ast, struct sip_pvt *p
 		return &ast_null_frame;
 
 	/* We already hold the channel lock */
-	if (!p->owner || f->frametype != AST_FRAME_VOICE)
+	if (!p->owner || (f && f->frametype != AST_FRAME_VOICE))
 		return f;
 
-	if (f->subclass != (p->owner->nativeformats & AST_FORMAT_AUDIO_MASK)) {
+	if (f && f->subclass != (p->owner->nativeformats & AST_FORMAT_AUDIO_MASK)) {
 		if (!(f->subclass & p->jointcapability)) {
 			if (option_debug) {
 				ast_log(LOG_DEBUG, "Bogus frame of format '%s' received from '%s'!\n",
@@ -4565,7 +4565,7 @@ static struct ast_frame *sip_rtp_read(struct ast_channel *ast, struct sip_pvt *p
 		ast_set_write_format(p->owner, p->owner->writeformat);
 	}
 
-	if ((ast_test_flag(&p->flags[0], SIP_DTMF) == SIP_DTMF_INBAND) && p->vad) {
+	if (f && (ast_test_flag(&p->flags[0], SIP_DTMF) == SIP_DTMF_INBAND) && p->vad) {
 		f = ast_dsp_process(p->owner, p->vad, f);
 		if (f && f->frametype == AST_FRAME_DTMF) {
 			if (ast_test_flag(&p->t38.t38support, SIP_PAGE2_T38SUPPORT_UDPTL) && f->subclass == 'f') {