{"id":"CVE-2026-41486","aliases":["GHSA-mw35-8rx3-xf9r","PYSEC-2026-2272","PYSEC-2026-2296"],"url":"https://o3.security/vulnerability/CVE-2026-41486","summary":"Ray: Remote Code Execution via Parquet Arrow Extension Type Deserialization","details":"Ray Data registers custom Arrow extension types (`ray.data.arrow_tensor`, `ray.data.arrow_tensor_v2`, `ray.data.arrow_variable_shaped_tensor`) globally in PyArrow. When PyArrow reads a Parquet file containing one of these extension types, it calls `__arrow_ext_deserialize__` on the field's metadata bytes. Ray's implementation passes these bytes directly to `cloudpickle.loads()`, achieving arbitrary code execution during schema parsing, before any row data is read.\n\nIn May 2024, Ray fixed a related vulnerability in `PyExtensionType`-based extension types ([issue #41314](https://github.com/ray-project/ray/issues/41314), [PR #45084](https://github.com/ray-project/ray/pull/45084)). In July 2025, [PR #54831](https://github.com/ray-project/ray/pull/54831) introduced `cloudpickle.loads()` into the replacement extension types' deserialization path, reintroducing the same class of vulnerability.\n\n## Impact\n\n- **Affected versions**: Ray 2.49.0 through 2.54.0 (latest release as of March 2026). The vulnerable `_deserialize_with_fallback` function with `cloudpickle.loads()` was introduced in commit `f6d21db1a4` ([PR #54831](https://github.com/ray-project/ray/pull/54831), July 2025), first released in Ray 2.49.0.\n- **Affected configurations**: Any process that uses Ray Data and reads Parquet files. The extension types are registered globally in PyArrow, so all Parquet reads in the process are affected, including `ray.data.read_parquet()`, `pyarrow.parquet.read_table()`, `pandas.read_parquet()`, etc.\n- **Attacker prerequisites**: The attacker must place a crafted Parquet file where a Ray Data pipeline reads it. No authentication or cluster access is required. The Parquet file must contain a column with a `ray.data.arrow_tensor` (or v2, or variable-shaped) extension type name, which makes this a targeted attack against Ray Data users.","published":"2026-05-08T21:46:14.442Z","modified":"2026-10-28T11:13:18.913489020Z","cvss":null,"epss":{"score":0.00473,"percentile":0.38783,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"ray","fixedVersion":"2.55.0"}],"fix":{"url":"https://github.com/ray-project/ray/commit/c02bd31ae31996805868baa446a131a8d304525f","label":"ray-project/ray@c02bd31"},"references":[{"type":"WEB","url":"https://github.com/ray-project/ray/releases/tag/ray-2.55.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41486.json"},{"type":"ADVISORY","url":"https://github.com/ray-project/ray/security/advisories/GHSA-mw35-8rx3-xf9r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41486"},{"type":"FIX","url":"https://github.com/ray-project/ray/commit/c02bd31ae31996805868baa446a131a8d304525f"},{"type":"FIX","url":"https://github.com/ray-project/ray/pull/62056"},{"type":"WEB","url":"https://github.com/ray-project/ray/pull/54831"},{"type":"PACKAGE","url":"https://github.com/ray-project/ray"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T11:13:18.913489020Z"}}