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AI agent vulnerability · Transformers

CVE-2026-80047: Hugging Face Transformers downloads custom generation code before trust consent

highCVSS 3.1 7.8GHSA-x9r9-c232-4q39

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.loadcustomgenerate(). The function fetches and caches a remote module file before performing the required trustremotecode consent check, inverting the security model enforced by other code-loading paths (such as AutoConfig,…

Published Sep 1, 2026 · Updated Sep 30, 2026

Affected packages

transformers

Ecosystem
PyPI
Affected
>= 4.49.0, <= 5.8.1
Fixed in
No patched version yet
Check
pip show transformers

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

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.

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

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