diff --git a/3rd/msgpack/src/bindings.c b/3rd/msgpack/src/bindings.c
index 84a4df55..e1499c0c 100644
--- a/3rd/msgpack/src/bindings.c
+++ b/3rd/msgpack/src/bindings.c
@@ -88,7 +88,7 @@ static bool mpack_to_py(mpack_node_t node) {
             if(!mpack_to_py_ext) {
                 return RuntimeError("msgpack: mpack_to_py_ext is not set, cannot handle ext type");
             }
-            if(!mpack_to_py_ext(node)) return false;
+            if(!mpack_to_py_ext(tmp, node)) return false;
             break;
         }
         default: return ValueError("msgpack: invalid node type");