CVE-2026-4538

A vulnerability was identified in PyTorch 2.10.0. The affected element is an unknown function of the component pt2 Loading Handler. The manipulation leads to deserialization. The attack can only be performed from a local environment. The exploit is publicly available and might be used. The project was informed of the problem early through a pull request but has not reacted yet.

An adversary with access to a shared model repository or artifact store (e.g., an internal MLflow registry, an S3 bucket, or a shared NFS mount used by a training cluster) crafts a malicious .pt2 file embedding a deserialization payload. When an automated pipeline or data scientist loads the file via PyTorch's pt2 Loading Handler, the payload executes in the process context — potentially establishing a reverse shell, exfiltrating environment variables and cloud credentials, or poisoning the training environment. In multi-tenant GPU clusters where researchers share model checkpoints, the local access requirement is trivially satisfied by any authenticated cluster user.