diff --git a/include/picotls.h b/include/picotls.h
index 0c72fa2..cac5a9c 100644
--- a/include/picotls.h
+++ b/include/picotls.h
@@ -1475,7 +1475,7 @@
 inline void ptls_buffer_dispose(ptls_buffer_t *buf)
 {
     ptls_buffer__release_memory(buf);
-    *buf = (ptls_buffer_t){NULL, 0, 0, 0};
+    *buf = (ptls_buffer_t){NULL, 0, 0, 0, 0};
 }
 
 inline uint8_t *ptls_encode_quicint(uint8_t *p, uint64_t v)