Affected: gitpython-developers GitPython

GitPython 3.1.59 fails to restrict the --no-index option in the high-level diff API, allowing attackers to read arbitrary filesystem paths as repository operands. Attackers can combine --no-index with -I/--ignore-matching-lines to create a content-dependent Boolean oracle, repeatedly querying local files to recover single-line secrets through distinguishable success or error responses.

Affected: PyPI: gitpython

### Summary

GitPython 3.1.59 blocks a previously available local-file read path through unsafe git diff options such as -O/--orderfile.

However, the high-level diff API still permits --no-index with the default allow_unsafe_options=False.

--no-index changes the semantics of the paths arguments: instead of repository-relative pathspecs, Git interprets them as arbitrary filesystem paths.

When combined with the still-allowed -I/--ignore-matching-lines option, this creates a content-dependent Boolean oracle over a caller-selected local file.

This was reproduced against the published GitPython 3.1.59 wheel.

The original unsafe-option path is blocked in 3.1.59, while this alternate path remains reachable without setting allow_unsafe_options=True.

### Details

Confirmed API surface:

repo.index.diff( None, no_index=True, I=pattern, paths=[baseline_path, target_path], create_patch=True, )

The relevant behavior is:

1. --no-index makes the two values supplied via paths filesystem operands rather than repository pathspecs. 2. -I/--ignore-matching-lines makes Git's result depend on whether the supplied regular expression matches the relevant file content. 3. GitPython exposes the resulting bit through distinguishable behavior: - matching condition: normal return with an empty DiffIndex - non-matching condition: GitCommandError with exit status 1

An application that forwards attacker-influenced diff options and paths and exposes the success/error disti…

Affected: PyPI: gitpython

GitPython 3.1.59 fails to restrict the --no-index option in the high-level diff API, allowing attackers to read arbitrary filesystem paths as repository operands. Attackers can combine --no-index with -I/--ignore-matching-lines to create a content-dependent Boolean oracle, repeatedly querying local files to recover single-line secrets through distinguishable success or error responses.