diff --git a/pymysqlreplication/packet.py b/pymysqlreplication/packet.py
index a5a7c0fd..c6eae5d5 100644
--- a/pymysqlreplication/packet.py
+++ b/pymysqlreplication/packet.py
@@ -343,6 +343,9 @@ def unpack_int32(self, n):
 
     def read_binary_json(self, size):
         length = self.read_uint_by_size(size)
+        if length == 0:
+            # handle NULL value
+            return None
         payload = self.read(length)
         self.unread(payload)
         t = self.read_uint8()