GHSA-mw35-8rx3-xf9r — ray
Fix: ray-project/ray#54831GHSA-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
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
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
rayReal-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_fallbackfunction withcloudpickle.loads()was introduced in commitf6d21db1a4(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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | ray | ≥ 2.49.0&&< 2.55.0 | 2.55.0pip install --upgrade 'ray==2.55.0' |
Detection & mitigation playbook
Open-source dependencyDetect
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.
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.
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.
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
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.