---
id: CVE-2026-57516
title: Ray < 2.56.0 Unsafe Deserialization RCE via WebDataset Reader
summary: >-
  Ray prior to 2.56.0 contains an unsafe deserialization vulnerability in the
  WebDataset reader that allows attackers to achieve remote code execution by
  supplying a malicious tar archive to the read_webdataset() function. The
  _default_dec…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-502
vendor: 'Anyscale, Inc'
product: Ray
affected:
  - Ray < 2.56.0
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-07-01T17:53:01.380220Z'
exploitAvailable: true
published: '2026-07-01'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T14:17:52.708Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-57516'
references:
  - url: 'https://github.com/ray-project/ray/releases/tag/ray-2.56.0'
    label: Release Notes
  - url: 'https://github.com/ray-project/ray/security/advisories/GHSA-hhrp-gw25-jr43'
    label: GitHub Security Advisory (GHSA-hhrp-gw25-jr43)
  - url: 'https://github.com/ray-project/ray/pull/63469'
    label: Fix PR (1)
  - url: 'https://github.com/ray-project/ray/pull/63470'
    label: Fix PR (2)
  - url: >-
      https://www.vulncheck.com/advisories/ray-unsafe-deserialization-rce-via-webdataset-reader
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-57516.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-57516'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2496087'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-57516'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-57516'
  - url: 'https://access.redhat.com/errata/RHSA-2026:61627'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68699'
  - url: >-
      https://github.com/ray-project/ray/commit/41443a18f9e6403a072de69098a279c23e2d943c
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/ray/PYSEC-2026-2273.yaml
  - url: 'https://github.com/ray-project/ray'
tags:
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
  - osv
  - pip
epss: 0.00858
epssPercentile: 0.56777
aliases:
  - GHSA-hhrp-gw25-jr43
  - PYSEC-2026-2273
ecosystem: pip
patched:
  - ai_inference_server 3.2
  - ai_inference_server 3.3
ingestedAt: '2026-07-13T18:58:08.788Z'
---

## Overview

Ray prior to 2.56.0 contains an unsafe deserialization vulnerability in the WebDataset reader that allows attackers to achieve remote code execution by supplying a malicious tar archive to the read_webdataset() function. The _default_decoder() function in webdataset_datasource.py unconditionally calls pickle.loads() on tar entries with .pkl/.pickle extensions and torch.load() with weights_only=False on .pt/.pth entries, executing arbitrary code inside Ray remote workers on every worker that processes the malicious archive.

## Affected

- `Ray < 2.56.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-57516)

Affected packages:

- `ray < 2.56.0`

Patched in:

- `ray 2.56.0`

Source: https://osv.dev/vulnerability/GHSA-hhrp-gw25-jr43

## Vendor advisories

- **RHSA-2026:61627** · Red Hat · fixed in: Red Hat AI Inference Server 3.2 · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:61627)
- **RHSA-2026:68699** · Red Hat · fixed in: Red Hat AI Inference Server 3.3 · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68699)
- **Red Hat VEX** · Important · affected: Red Hat AI Inference Server, Red Hat Enterprise Linux AI (RHEL AI) 3, Red Hat OpenShift AI (RHOAI) · no fix planned: Red Hat AI Inference Server, Red Hat Enterprise Linux AI (RHEL AI) 3, Red Hat OpenShift AI (RHOAI) · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-57516.json)