CVE-2026-41486 Details

A remote code execution vulnerability exists in Ray versions 2.54.0 prior to 2.55.0. The issue arises in the Ray Data component, which registers custom Arrow extension types globally in PyArrow. When PyArrow processes a Parquet file containing these extension types, it invokes the `__arrow_ext_deserialize__` method on the field's metadata bytes. Ray's handling of this metadata directly passes the bytes to `cloudpickle.loads()`, leading to arbitrary code execution during schema parsing, before any actual row data is accessed. This vulnerability affects any process using Ray Data that reads Parquet files with the registered extension types.

Users can upgrade to Ray version 2.55.0 or later, where this vulnerability has been patched.