LMDeploy vulnerable to arbitrary code execution via eval() of untrusted quant_dtype in model config loading

GHSA-3hmm-rh5q-gwwr

Primary source · Revision 1

PYSEC-2026-4078

Revision 2

LMDeploy vulnerable to arbitrary code execution via eval() of untrusted quant_dtype in model config loading

### Summary lmdeploy <= latest contains a code injection vulnerability in `lmdeploy/pytorch/config.py` line 620 that allows an attacker to execute arbitrary Python code by publishing a malicious HuggingFace model with a crafted `quantization_config.quant_dtype` value. When a user loads the model with lmdeploy, the `quant_dtype` is passed to `eval(f'torch.{quant_dtype}')` without any validation. ### Details **Vulnerable code** ([permalink](https://github.com/InternLM/lmdeploy/blob/17ed9e5/lmdeploy/pytorch/config.py#L620)): ```python quant_dtype = eval(f'torch.{quant_dtype}') # line 620 ``` The `quant_dtype` value comes from the model's `quantization_config` in its HuggingFace config. When a model specifies `quant_method: awq`, the AWQ branch processes the config but does NOT override `quant_dtype`, allowing the malicious value to reach the `eval()` call. **Attack vector:** An attacker publishes a HuggingFace model with: ```json { "quantization_config": { "quant_method": "awq", "quant_dtype": "float16, __import__('os').system('id')" } } ``` Note: The `_update_torch_dtype` method at line 53 has a whitelist check, but that's for `torch_dtype`, NOT `quant_dtype`. The `quant_dtype` at line 620 has no validation whatsoever. ### PoC ```python """ PoC: eval() RCE in lmdeploy via malicious quant_dtype Prerequisites: pip install lmdeploy """ import sys from unittest.mock import MagicMock, patch # Mock torch to capture the eval sys.modules.setdefault('torch', MagicMock()) from lmdeploy.p