CVE-2026-1839: Arbitrary Code Execution via Unsafe torch.load() in Trainer Checkpoint Loading in huggingface/transformers

A vulnerability in the HuggingFace Transformers library, specifically in the Trainer class, allows for arbitrary code execution. The loadrngstate() method in src/transformers/trainer.py at line 3059 calls torch.load() without the weightsonly=True parameter. This issue affects all versions of the library supporting torch>=2.2 when used with PyTorch versions below 2.6, as the safeglobals() context manager provides no protection in these versions. An attacker can exploit this vulnerability by supplying a malicious checkpoint file, such as rngstate.pth, which can execute arbitrary code when loaded. The issue is resolved in version v5.0.0rc3.