| # fastsafetensors header DoS — PoC model file | |
| Security proof-of-concept for a Denial-of-Service in | |
| [`foundation-model-stack/fastsafetensors`](https://github.com/foundation-model-stack/fastsafetensors) | |
| (HEAD `8d35826`). Reported via huntr's Model File Vulnerability program. | |
| `model.safetensors` is a ~80-byte safetensors file whose header carries a tensor | |
| entry with an **invalid `dtype`**. Loading it crashes the parser with an uncaught | |
| `ValueError`, before any tensor data is read. This affects any app using | |
| fastsafetensors, including vLLM / SGLang started with `--load-format fastsafetensors`. | |
| ## Reproduce | |
| ```python | |
| from fastsafetensors.common import SafeTensorsMetadata | |
| from fastsafetensors.frameworks import get_framework_op | |
| SafeTensorsMetadata.from_file("model.safetensors", get_framework_op("pytorch")) | |
| # -> ValueError: 'NOTADTYPE' is not a valid DType (uncaught -> loader crash) |