diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 19039c68eb..fdf1ffcfd5 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -3938,7 +3938,7 @@ static enum sip_result __sip_reliable_xmit(struct sip_pvt *p, int seqno, int res
 		}
 	}
 
-	if (!(pkt = ast_calloc(1, sizeof(*pkt) + len + 1)))
+	if (!(pkt = ast_calloc(1, sizeof(*pkt))))
 		return AST_FAILURE;
 	/* copy data, add a terminator and save length */
 	if (!(pkt->data = ast_str_create(len))) {