validate byte_count

pymodbus-dev · Jul 23, 2024 · cd0050c · cd0050c
1 parent 857ddf2
commit cd0050c
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/pymodbus/pdu/register_read_message.py b/pymodbus/pdu/register_read_message.py
@@ -4,6 +4,7 @@
 # pylint: disable=missing-type-doc
 import struct
 
+from pymodbus.exceptions import ModbusIOException
 from pymodbus.pdu import ModbusExceptions as merror
 from pymodbus.pdu import ModbusRequest, ModbusResponse
 
@@ -88,6 +89,8 @@ def decode(self, data):
         :param data: The request to decode
         """
         byte_count = int(data[0])
+        if byte_count < 2 or byte_count > 246 or byte_count != len(data) - 1:
+            raise ModbusIOException(f"Invalid response {data} has byte count of {byte_count}")
         self.registers = []
         for i in range(1, byte_count + 1, 2):
             self.registers.append(struct.unpack(">H", data[i : i + 2])[0])