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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.004 (30.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 30.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.000
Affected products
- Huggingface Huggingface/transformers — versions unspecified
- Huggingface Transformers — versions 5.0.0
Weakness classification (CWE)
References
- huntr.com/bounties/3c77bb97-e493-493d-9a88-c57f5c536485 (Exploit, Third Party Advisory)
- github.com/huggingface/transformers/commit/03c8082ba4594c9b8d6fe190ca9bed0e5f8c… (Patch)
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.