huggingface transformers up to 5.0.0rc2 trainer.py _load_rng_state deserialization

Summaryinfo

A vulnerability was found in huggingface transformers up to 5.0.0rc2 and classified as problematic. This impacts the function _load_rng_state of the file src/transformers/trainer.py. The manipulation results in deserialization. This vulnerability is identified as CVE-2026-1839. The attack is only possible with local access. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in huggingface transformers up to 5.0.0rc2. Affected is the function _load_rng_state of the file src/transformers/trainer.py. The manipulation with an unknown input leads to a deserialization vulnerability. CWE is classifying the issue as CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at huntr.com. This vulnerability is traded as CVE-2026-1839 since 02/03/2026. The exploitability is told to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available.

Upgrading to version 5.0.0rc3 eliminates this vulnerability. Applying the patch 03c8082ba4594c9b8d6fe190ca9bed0e5f8ca396 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• huggingface

Name

• transformers

Version

• 5.0.0rc1
• 5.0.0rc2

License

• open-source

Website

• Product: https://github.com/huggingface/transformers/

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion