diff --git a/thermometer/thermometer.c b/thermometer/thermometer.c
index c2256b6..614da18 100644
--- a/thermometer/thermometer.c
+++ b/thermometer/thermometer.c
@@ -48,6 +48,8 @@
 
 #define FLOAT_MAX_MANTISSA	16777216 /* 2^24 */
 
+#define VALID_RANGE_DESC_SIZE	4
+
 struct thermometer {
 	DBusConnection		*conn;		/* The connection to the bus */
 	struct btd_device	*dev;		/* Device reference */
@@ -297,7 +299,7 @@ static void valid_range_desc_cb(guint8 status, const guint8 *pdu, guint16 len,
 							gpointer user_data)
 {
 	struct descriptor *desc = user_data;
-	uint8_t value[ATT_MAX_MTU];
+	uint8_t value[VALID_RANGE_DESC_SIZE];
 	uint16_t max, min;
 	ssize_t vlen;