What’s Vulnerable › Vulnerabilities

CVE-2026-57516: Ray < 2.56.0 Unsafe Deserialization RCE via WebDataset Reader

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-01 · updated 2026-10-25
• Weakness: CWE-502

Description

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 products

• ray-project ray: before 2.56.0 — fixed in 2.56.0

How to fix

Upgrade to a fixed version: ray-project ray 2.56.0. Check the vendor advisory for mitigations.

References

• https://github.com/ray-project/ray/pull/63469
• https://github.com/ray-project/ray/pull/63470
• https://github.com/ray-project/ray/releases/tag/ray-2.56.0
• https://github.com/ray-project/ray/security/advisories/GHSA-hhrp-gw25-jr43
• https://www.vulncheck.com/advisories/ray-unsafe-deserialization-rce-via-webdataset-reader
• https://github.com/ray-project/ray/security/advisories/GHSA-hhrp-gw25-jr43

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