skops is a Python library which helps users share and ship their scikit-learn based models. In versions 0.12.0 and below, the Card.get_model does not contain any logic to prevent arbitrary code execution. The Card.get_model function supports both joblib and skops for model loading. When loading .skops models, it uses skops' secure loading with trusted type validation, raising errors for untrusted types unless explicitly allowed. However, when non-.zip file formats are provided, the function silently falls back to joblib without warning. Unlike skops, joblib allows arbitrary code execution during loading, bypassing security measures and potentially enabling malicious code execution. This issue is fixed in version 0.13.0.

Affected: PyPI: skops

## Summary

The `Card` class of `skops`, used for model documentation and sharing, allows arbitrary code execution. When a file other than `.zip` is provided to the `Card` class during instantiation, the internally invoked `Card.get_model` method silently falls back to `joblib` without warning. Unlike the `.skops` zip-based format, `joblib` permits unrestricted code execution, hence bypassing the security measures of `skops` and enabling the execution of malicious code.

## Details

The `Card` class supports loading the model linked to the card using the `get_model` method. When a `.skops` model is provided, it uses the `load` function from `skops`, which includes security mechanisms. The `Card` class also supports consistent management of the `trusted` list, which can be passed during instance creation. As expected, if a `.skops` model is provided without a `trusted` list and an untrusted type is encountered during loading, an error is raised. This behavior is consistent with the security principles of `skops`.

The problem arises when a file format other than `.zip` is provided. As shown in the code snippet below, in this case, the `joblib` library is used to load the model. This happens **silently**, without any warning or indication that `joblib` is being used. This is a significant security risk because `joblib` does not enforce the same security measures as `skops`, allowing arbitrary code execution.

```python # from `card/_model_card.py:354-358` try: if zipfile.…

Affected: PyPI: skops

## Summary

The `Card` class of `skops`, used for model documentation and sharing, allows arbitrary code execution. When a file other than `.zip` is provided to the `Card` class during instantiation, the internally invoked `Card.get_model` method silently falls back to `joblib` without warning. Unlike the `.skops` zip-based format, `joblib` permits unrestricted code execution, hence bypassing the security measures of `skops` and enabling the execution of malicious code.

## Details

The `Card` class supports loading the model linked to the card using the `get_model` method. When a `.skops` model is provided, it uses the `load` function from `skops`, which includes security mechanisms. The `Card` class also supports consistent management of the `trusted` list, which can be passed during instance creation. As expected, if a `.skops` model is provided without a `trusted` list and an untrusted type is encountered during loading, an error is raised. This behavior is consistent with the security principles of `skops`.

The problem arises when a file format other than `.zip` is provided. As shown in the code snippet below, in this case, the `joblib` library is used to load the model. This happens **silently**, without any warning or indication that `joblib` is being used. This is a significant security risk because `joblib` does not enforce the same security measures as `skops`, allowing arbitrary code execution.

```python # from `card/_model_card.py:354-358` try: if zipfile.…