diff --git a/tasmota/tasmota_xdrv_driver/xdrv_63_modbus_bridge.ino b/tasmota/tasmota_xdrv_driver/xdrv_63_modbus_bridge.ino
index 1b4f8027b..7958fe388 100644
--- a/tasmota/tasmota_xdrv_driver/xdrv_63_modbus_bridge.ino
+++ b/tasmota/tasmota_xdrv_driver/xdrv_63_modbus_bridge.ino
@@ -562,7 +562,7 @@ void CmndModbusBridgeSend(void)
     }
     else
     {
-      writeData = (uint16_t *)malloc(writeDataSize);
+      writeData = (uint16_t *)malloc(writeDataSize*2);
       for (uint8_t jsonDataArrayPointer = 0; jsonDataArrayPointer < writeDataSize; jsonDataArrayPointer++)
       {
         writeData[jsonDataArrayPointer] = jsonDataArray[jsonDataArrayPointer].getUInt(0);