Bug 2496087 (CVE-2026-57516)

Summary:	CVE-2026-57516 ray: Ray: Remote code execution via unsafe deserialization in WebDataset reader
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	alinfoot, bbrownin, dtrifiro, rbryant, weaton
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in Ray. This unsafe deserialization vulnerability in the WebDataset reader allows a remote attacker to achieve arbitrary code execution. By supplying a specially crafted malicious tar archive to the read_webdataset() function, an attacker can trigger the unconditional deserialization of .pkl/.pickle or .pt/.pth entries, leading to the execution of arbitrary code within Ray remote workers.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-01 18:01:41 UTC

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.