Deserialization in Huggingface Huggingface/transformers

CVE-2026-1839

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.

Vulnerability class: Insecure Deserialization

EPSS: 0.003 (27.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-1839?
CVE-2026-1839 is a high-severity vulnerability in Huggingface Huggingface/transformers, classified under Deserialization of Untrusted Data. CVSS score: 7.8/10. Published 2026-04-07.
How severe is CVE-2026-1839?
High severity. CVSS v3 base score is 7.8 out of 10.