---
id: GHSA-whh4-5q6c-9v3x
title: >-
  GitPython: --no-index bypasses diff unsafe-option protections and enables a
  blind local-file content oracle
summary: >-
  GitPython: --no-index bypasses diff unsafe-option protections and enables a
  blind local-file content oracle
severity: medium
cvss: 6.5
cwe:
  - CWE-88
  - CWE-200
vendor: gitpython
product: gitpython
ecosystem: pip
affected:
  - 'gitpython >= 3.1.59, < 3.1.60'
patched:
  - gitpython 3.1.60
published: '2026-09-30'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T23:28:41Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-whh4-5q6c-9v3x'
references:
  - url: >-
      https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-whh4-5q6c-9v3x
  - url: 'https://github.com/gitpython-developers/GitPython/pull/2217'
  - url: >-
      https://github.com/gitpython-developers/GitPython/commit/09f2cf383a992d1af697364569e9f384748c1bd8
  - url: 'https://github.com/gitpython-developers/GitPython/releases/tag/3.1.60'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/gitpython/PYSEC-2026-3983.yaml
  - url: >-
      https://www.vulncheck.com/advisories/gitpython-3.1.59-local-file-content-oracle-via-no-index
  - url: 'https://github.com/advisories/GHSA-whh4-5q6c-9v3x'
tags:
  - ghsa
  - pip
ingestedAt: '2026-09-30T23:29:32.581Z'
---

## Overview

### 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 distinction can therefore be queried repeatedly to recover a guessable local single-line secret.

The issue was confirmed with the default allow_unsafe_options=False.

The behavior does not require the caller to explicitly opt into GitPython's unsafe-option mode.

Verified intended security boundary:

- GitPython 3.1.58 accepts the earlier -O/--orderfile local-file input path.
- GitPython 3.1.59 rejects that same path with UnsafeOptionError.
- GitPython 3.1.59 still permits the --no-index alternate path described above.

This appears to be an alternate route to the same local-file confidentiality property that the 3.1.59 diff option hardening is intended to protect.

### PoC

A minimal reproducer, controlled extraction demonstrator, proof matrix, and proposed remediation are included in the attached package.

[gitpython-3159-maintainer-evidence.zip](https://github.com/user-attachments/files/31123571/gitpython-3159-maintainer-evidence.zip)


The minimal reproducer creates only temporary researcher-controlled files and demonstrates the following predicate:

correct prefix   -> normal GitPython return
incorrect prefix -> GitCommandError(status=1)

In the controlled extraction test, I generated three independent random single-line values and recovered all three exactly through repeated calls to the GitPython high-level API.

Result: 3/3 recovered.

The extraction harness also installs a Python audit hook that rejects direct Python open() access to the target file during the oracle phase. The content-dependent read is therefore performed by the child git process invoked through GitPython rather than by the reproduction script directly.

Controls were also tested:

- normal repository-scoped diff: no secret disclosure
- same outside paths without --no-index: no arbitrary-filesystem interpretation
- deliberately incorrect predicate: status 1 as expected

Suggested remediation is to classify --no-index as unsafe for the high-level diff API unless the caller explicitly sets allow_unsafe_options=True.

### Impact

Potential impact is disclosure of local files readable by the process running GitPython.

Exploitation requires an embedding application to allow an attacker to influence:

1. the relevant diff options,
2. both path operands, and
3. repeated requests while exposing a distinguishable success/error result.

The demonstrated attack is a blind content oracle rather than a one-request in-band file read. It is particularly applicable to short or structured single-line secrets where the target path and approximate value format are known or guessable.

Confirmed affected release: GitPython 3.1.59.

## Affected packages

- `gitpython >= 3.1.59, < 3.1.60`

## Remediation

Upgrade to a patched release:

- `gitpython 3.1.60`