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GHSA-mw35-8rx3-xf9r — ray

Fix: ray-project/ray#54831

GHSA-mw35-8rx3-xf9r is a Code Injection vulnerability in ray. A fix is available for ray — see the affected versions and patch details below.

Ray: Remote Code Execution via Parquet Arrow Extension Type Deserialization

Also known asCVE-2026-41486PYSEC-2026-2272PYSEC-2026-2296
Published
Apr 24, 2026
Updated
Sep 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-mw35-8rx3-xf9r.

EPSS Exploitation Probability

via FIRST.org ↗
0.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs51th percentile — riskier than 51% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected
🐍ray

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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.

In May 2024, Ray fixed a related vulnerability in PyExtensionType-based extension types (issue #41314, PR #45084). In July 2025, PR #54831 introduced cloudpickle.loads() into the replacement extension types' deserialization path, reintroducing the same class of vulnerability.

Impact

  • 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, July 2025), first released in Ray 2.49.0.
  • 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.
  • 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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIray≥ 2.49.0&&< 2.55.02.55.0pip install --upgrade 'ray==2.55.0'

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ray, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update ray to 2.55.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mw35-8rx3-xf9r is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-mw35-8rx3-xf9r can be triaged on real exposure rather than presence alone.

Tailored to GHSA-mw35-8rx3-xf9r. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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. In May 2024, Ray fixed a related vulnerability in `PyExtensionType`-based extension types ([issue #41314](https://github.com/ray-p
O3 Security · Impact-Aware SCA

Is GHSA-mw35-8rx3-xf9r in your dependencies?

O3 Security finds GHSA-mw35-8rx3-xf9r across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-mw35-8rx3-xf9r: ray RCE | O3 Security