diff --git a/coreapi/sal_eXosip2_sdp.c b/coreapi/sal_eXosip2_sdp.c
index fd6d959d5f00a74626345f64302b0439f4d8869e..848e3070c9986ba95cf96d8a7a0c8d408729b67c 100644
--- a/coreapi/sal_eXosip2_sdp.c
+++ b/coreapi/sal_eXosip2_sdp.c
@@ -185,7 +185,7 @@ static void add_payload(sdp_message_t *msg, int line, const PayloadType *pt)
 
 
 static void add_line(sdp_message_t *msg, int lineno, const SalStreamDescription *desc){
-	const char *mt;
+	const char *mt=NULL;
 	const MSList *elem;
 	const char *addr;
 	const char *dir="sendrecv";