diff --git a/sonoff/sonoff.ino b/sonoff/sonoff.ino
index 161c26ed8..2a65f8f65 100755
--- a/sonoff/sonoff.ino
+++ b/sonoff/sonoff.ino
@@ -431,6 +431,8 @@ uint16_t GetPulseTimer(uint8_t index)
 
 void MqttDataHandler(char* topic, uint8_t* data, unsigned int data_len)
 {
+  if (data_len > MQTT_MAX_PACKET_SIZE) { return; }  // Do not allow more data than would be feasable within stack space
+
   char *str;
 
   if (!strcmp(Settings.mqtt_prefix[0],Settings.mqtt_prefix[1])) {