diff --git a/scapy/utils.py b/scapy/utils.py
index c86b09cbf72..c9d673c9244 100644
--- a/scapy/utils.py
+++ b/scapy/utils.py
@@ -1786,7 +1786,7 @@ def _read_packet(self, size=MTU):  # type: ignore
 
         """
         while True:
-            res = self._read_block()
+            res = self._read_block(size=size)
             if res is not None:
                 return res