CVE-2026-1839: HuggingFace Transformers allows for arbitrary code execution in the `Trainer` class

CVE-2026-1839 · Severity: high · CVSS 7.8 · Published 2026-04-07

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

Technologies: Huggingface Transformers, transformers (PyPI). Vendors: Huggingface, PyPI.

Quick answers

Is CVE-2026-1839 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-1839 being exploited in the wild.
How severe is CVE-2026-1839?
High severity, with a CVSS score of 7.8, published 7 April 2026.
Which products and versions are affected?
transformers (PyPI) ECOSYSTEM:introduced=0,fixed=5.0.0, ECOSYSTEM:introduced=0,fixed=5.0.0rc3.
Is there a fix for CVE-2026-1839?
Yes. transformers (PyPI): upgrade to 5.0.0, 5.0.0rc3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-1839?
Check whether you run Huggingface Transformers or transformers (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • transformers (PyPI): upgrade to 5.0.0, 5.0.0rc3 or later
    pip install "transformers>=5.0.0rc3"

Affected products

  • Huggingface Transformers
  • transformers (PyPI) ECOSYSTEM:introduced=0,fixed=5.0.0, ECOSYSTEM:introduced=0,fixed=5.0.0rc3

Identifiers

  • CVE-2026-1839
  • GHSA-69w3-r845-3855
  • PYSEC-2026-2288

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