PYSEC-2026-2010

Description

# Summary vLLM loads Hugging Face `auto_map` dynamic modules during model resolution **without gating on `trust_remote_code`**, allowing attacker-controlled Python code in a model repo/path to execute at server startup. --- # Impact An attacker who can influence the model repo/path (local directory or remote Hugging Face repo) can achieve **arbitrary code execution** on the vLLM host during model load. This happens **before any request handling** and does **not require API access**. --- # Affected Versions All versions where `vllm/model_executor/models/registry.py` resolves `auto_map` entries with `try_get_class_from_dynamic_module` **without checking `trust_remote_code`** (at least current `main`). --- # Details During model resolution, vLLM unconditionally iterates `auto_map` entries from the model config and calls `try_get_class_from_dynamic_module`, which delegates to Transformers’ `get_class_from_dynamic_module` and **executes the module code**. This occurs even when `trust_remote_code` is `false`, allowing a malicious model repo to embed code in a referenced module and have it executed during initialization. ### Relevant code - `vllm/model_executor/models/registry.py:856` — auto_map resolution - `vllm/transformers_utils/dynamic_module.py:13` — delegates to `get_class_from_dynamic_module`, which executes code --- # Fixes * https://github.com/vllm-project/vllm/pull/32194 # Credits Reported by **bugbunny.ai**