Hugging Face Transformers downloads custom generation code before trust consent
A vulnerability in Hugging Face Transformers (versions 4.49.0, <= 5.8.1) allows remote Python files to be written to local disk without user consent when using GenerativePreTrainedModel.load_custom_generate(). The function fetches and caches a remote module file before performing the required trust_remote_code consent check, inverting the security model enforced by other code-loading paths (such as AutoConfig, AutoModel, and AutoTokenizer). As a result, attacker‑controlled Python code from custom_generate/generate.py is copied into the user’s ~/.cache/huggingface/modules directory even if the user declines the trust prompt. Although execution is correctly gated, the file write is not reversible and can persist across sessions. This can lead to persistent, unauthorized files on disk and stale cache collisions where cached attacker code may later be executed during trusted model loads. The issue stems from an unconditional file write in dynamic_module_utils.py prior to any trust verification.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | transformers | >= 4.49.0, <= 5.8.1 | no fix |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-80047
- https://github.com/huggingface/transformers/pull/48620
- https://github.com/huggingface/transformers/commit/cbc1651a032b923da7f4b44b3d0e6f68e6ba6b55
- https://github.com/huggingface/transformers
- https://kb.cert.org/vuls/id/456290
- https://www.kb.cert.org/vuls/id/456290
- https://pypi.org/project/transformers
- https://github.com/advisories/GHSA-x9r9-c232-4q39
- CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-273- Platform
- Python (PyPI)
- Package
transformers- Disclosed
- 01.09.2026
- Updated
- 11.10.2026 15:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-4174 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-x9r9-c232-4q39 - CC BY 4.0
Vulnerability history: transformers
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 32
- First → latest
- 05.2023 09.2026
- Without a fix
- 9
- Exploited in attacks
- 0
Severity breakdown
- High 18
- Medium 12
- Low 2
Disclosures per year
- 2023: 3
- 2024: 4
- 2025: 20
- 2026: 5
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