CVE-2026-57516 in Ray
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.
Quick answer
Anyscale Ray should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Ray before 2.56.0
Fixed versions
- Ray 2.56.0 or later
How to fix it
CVE-2026-57516 affects Ray. In simple terms, an attacker may run unsafe code if they can reach the vulnerable feature. Update to Ray 2.56.0 or later. If you cannot update today, limit who can reach this system until the fix is done.
- Find every place where Ray is installed or used.
- Check if the version matches: Ray before 2.56.0.
- Update to: Ray 2.56.0 or later.
- If you cannot update now, allow only trusted users and trusted networks.
- Check logs for crashes, strange requests, failed logins, or unexpected access.
- Change secrets or passwords if you think data may have been exposed.
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Verify the fix
- Confirm the installed version is now: Ray 2.56.0 or later.
- Confirm the risky feature is no longer exposed to untrusted users.
- Run the affected workflow again and make sure it still works.
- Review logs again after the update.
- Run a new Fixnx scan if this software is part of a public website.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-57516?
Anyscale Ray versions listed as affected should be reviewed: Ray before 2.56.0.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.