diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index d4798c7..9e1b425 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -1026,15 +1026,15 @@
 		return NULL;
 	}
 
-	/* look into the phone number */
-	if ((data_ptr[0] & 0x01) != 1)
-		return NULL;
-
 	if (data_len < 3) {
 		LOGP(DNAT, LOGL_ERROR, "SMS-SUBMIT is too short.\n");
 		return NULL;
 	}
 
+	/* look into the phone number */
+	if ((data_ptr[0] & 0x01) != 1)
+		return NULL;
+
 	dest_len = data_ptr[2];
 	if (data_len < dest_len + 3 || dest_len < 2) {
 		LOGP(DNAT, LOGL_ERROR, "SMS-SUBMIT can not have TP-DestAddr.\n");