diff --git a/kafka/protocol/schemas/fields/codecs/types.py b/kafka/protocol/schemas/fields/codecs/types.py
index e423cd02a..239e8fb15 100644
--- a/kafka/protocol/schemas/fields/codecs/types.py
+++ b/kafka/protocol/schemas/fields/codecs/types.py
@@ -341,6 +341,7 @@ def encode(cls, value, compact=False):
 
     @classmethod
     def encode_into(cls, out, value):
+        out.ensure(5)
         buf = out.buf
         pos = out.pos
         while (value & 0xffffff80) != 0: