# CVE-2026-57516: Ray unsafe deserialization in WebDataset and Parquet readers

Source: https://junglewise.ai/threats/cve-2026-57516-ray-unsafe-deserialization-in-webdataset-and-parquet-readers  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-01. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-57516 · Severity: high · CVSS 8.8 · Published 2026-07-01

Ray is a framework used for scaling Python and machine learning workloads. A vulnerability in its data-loading component allows an attacker to execute arbitrary code on a user's system if the user processes a specially crafted dataset file (WebDataset format). This could lead to full system compromise, data theft, or unauthorized access to cloud environments where Ray is running.

Technologies: [ray (PyPI)](https://junglewise.ai/threats/technologies/ray). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-57516 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-57516 being exploited in the wild.

**How severe is CVE-2026-57516?** High severity, with a CVSS score of 8.8, published 1 July 2026.

**Which products and versions are affected?** ray (PyPI) < 2.56.0, ECOSYSTEM:introduced=0,fixed=2.56.0.

**Is there a fix for CVE-2026-57516?** Yes. ray (PyPI): upgrade to 2.56.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-57516 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-57516?** Check whether you run ray (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- ray (PyPI): upgrade to 2.56.0 or later

  ```sh
  pip install "ray>=2.56.0"
  ```


## Technical details

The `ray.data.read_webdataset` API uses a default decoder that automatically processes file extensions within TAR archives. Specifically, files with `.pickle`/`.pkl` extensions are passed to `pickle.loads()`, and files with `.pt`/`.pth` extensions are passed to `torch.load()` with `weights_only=False`. Both of these functions are known to be unsafe when processing untrusted data as they allow for arbitrary object reconstruction and code execution. An attacker can trigger this by providing a malicious TAR file via a URL, S3 bucket, or other supported path. The vulnerability exists because these unsafe branches are enabled by default without user opt-in or validation. The issue was addressed in version 2.56.0 by requiring explicit configuration to load these formats.

## Affected products

- ray-project ray < 2.56.0

## Identifiers

- CVE-2026-57516
- GHSA-hhrp-gw25-jr43
- PYSEC-2026-2273

## Timeline

- 2026-07-01: advisory: GitHub Advisory published
- 2026-07-24: patched: Vulnerability fixed in version 2.56.0

## References

- [https://api.github.com/users/SSJCorpSec](https://api.github.com/users/SSJCorpSec)
- [https://github.com/SSJCorpSec](https://github.com/SSJCorpSec)
- [https://api.github.com/users/SSJCorpSec/gists%7B/gist_id%7D](https://api.github.com/users/SSJCorpSec/gists%7B/gist_id%7D)
- [https://api.github.com/users/SSJCorpSec/repos](https://api.github.com/users/SSJCorpSec/repos)
- [https://avatars.githubusercontent.com/u/220600175?v=4](https://avatars.githubusercontent.com/u/220600175?v=4)
- [https://api.github.com/users/SSJCorpSec/events%7B/privacy%7D](https://api.github.com/users/SSJCorpSec/events%7B/privacy%7D)

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- [PYSEC-2026-516 - Ray Missing Authorization vulnerability](https://junglewise.ai/threats/cve-2023-6020-ray-missing-authorization-vulnerability)
- [PYSEC-2026-519 - Ray OS Command Injection vulnerability](https://junglewise.ai/threats/cve-2023-6019-ray-os-command-injection-vulnerability)
- [Ray Ray Data remote code execution via Parquet deserialization](https://junglewise.ai/threats/cve-2026-41486-ray-ray-data-remote-code-execution-via-parquet-deserialization)