CVE-2026-57516

Name of the Vulnerable Software and Affected Versions Ray versions prior to 2.56.0

Description An unsafe deserialization issue exists in the WebDataset reader. An attacker can achieve remote code execution by providing 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 or .pickle extensions and torch.load() with weights only=False on .pt or .pth entries. This results in the execution of arbitrary code within Ray remote workers on every worker that processes the malicious archive. Deserialization is the process of converting a data format back into an object, which becomes unsafe when untrusted data is processed without validation.

Recommendations Update to version 2.56.0 or later. As a temporary mitigation, avoid using the read webdataset() function with untrusted tar archives.