diff --git a/src/mncc.c b/src/mncc.c
index 1b2aacf..02cda9c 100644
--- a/src/mncc.c
+++ b/src/mncc.c
@@ -656,7 +656,7 @@ int mncc_create_remote_leg(struct mncc_connection *conn, struct call *call,
 	memcpy(&mncc.calling.number, calling, sizeof(mncc.calling.number));
 
 	if (conn->app->use_imsi_as_id) {
-		snprintf(mncc.imsi, 16, called);
+		snprintf(mncc.imsi, 15, called);
 	} else {
 		mncc.fields |= MNCC_F_CALLED;
 		mncc.called.plan = 1;