CVE-2026-78676: GitPython Config Injection RCE Vulnerability

CVE-2026-78676 Overview

CVE-2026-78676 is a critical remote code execution vulnerability in GitPython versions before 3.1.59. The library fails to safely re-serialize multi-line git-config values during write operations. This flaw corrupts dormant quoted values into injected directives such as core.hooksPath. Attackers can craft config files with embedded newlines that become live git directives after any unrelated GitPython config write. Successful exploitation enables arbitrary code execution through hook invocation. The issue is tracked under CWE-88: Argument Injection or Modification and disclosed in GitHub Security Advisory GHSA-284h-m62q-gf8w.

Critical Impact
Attackers can achieve remote code execution on hosts running GitPython by planting a malicious .gitconfig that activates after any subsequent config write.

Affected Products

GitPython versions prior to 3.1.59
Python applications and CI/CD pipelines that use GitPython to read or write git configuration
Automated tooling that operates on untrusted repositories via GitPython

Discovery Timeline

2026-08-25 - CVE-2026-78676 published to NVD
2026-08-26 - Last updated in NVD database

Technical Details for CVE-2026-78676

Vulnerability Analysis

GitPython provides a Python interface to git repositories, including read and write access to git configuration files. The library uses a config parser that reads existing values, applies modifications, and re-serializes the full configuration back to disk. The re-serialization routine does not correctly escape or reject multi-line values containing embedded newline characters.

When a quoted value in an existing config contains a newline, GitPython preserves the value on read but writes it back without the surrounding quotes or escape handling. The written form places the payload after the newline on its own line, where the git config parser interprets it as a new directive. This transforms an inert quoted string into an active configuration entry such as core.hooksPath = /tmp/attacker.

Once core.hooksPath points to an attacker-controlled directory, subsequent git operations invoke hook scripts from that path. GitPython or the underlying git binary then executes attacker code in the context of the current user.

Root Cause

The root cause is unsafe re-serialization of git-config values in GitPython's config writer. The writer does not validate that values remain single-line after quote stripping. This mismatch between the parser's quote-aware read and the writer's naive output allows argument injection at write time.

Attack Vector

An attacker plants a crafted .gitconfig, .git/config, or included config file containing a quoted multi-line value. The value stays dormant until any process invokes GitPython to write to that configuration. On the next write, GitPython emits the payload as a live directive, enabling core.hooksPath hijacking and subsequent code execution during any git operation. Delivery vectors include malicious repositories cloned by CI runners, developer workstations, and shared build agents.

No verified exploit code is publicly available. See the VulnCheck advisory on GitPython config injection for further technical detail.

Detection Methods for CVE-2026-78676

Indicators of Compromise

Unexpected core.hooksPath entries in .git/config, .gitconfig, or included config files
Newly created hook scripts (pre-commit, post-checkout, post-merge) in non-standard directories
GitPython process trees spawning shells or interpreters immediately after git operations
Config files containing quoted values with embedded newline bytes (0x0A)

Detection Strategies

Scan repositories and user home directories for git-config values that contain literal newlines inside quoted strings
Alert on writes to .git/config or .gitconfig by Python processes importing git or GitPython
Correlate GitPython execution with subsequent child processes launched from non-standard hook paths
Compare pre- and post-write hashes of config files touched by GitPython-backed automation

Monitoring Recommendations

Monitor CI/CD build agents for changes to hook directories and core.hooksPath settings
Log all invocations of GitPython in security-sensitive automation with argument capture
Track outbound network connections initiated by processes spawned from git hooks

How to Mitigate CVE-2026-78676

Immediate Actions Required

Upgrade GitPython to version 3.1.59 or later across all environments
Audit CI/CD runners, developer laptops, and shared build hosts for tampered .gitconfig files
Reset core.hooksPath to a known-good value and remove unexpected hook scripts
Restrict GitPython automation to trusted repositories and disable execution on untrusted input where feasible

Patch Information

The fix ships in GitPython 3.1.59. Refer to GitHub Security Advisory GHSA-284h-m62q-gf8w for the vendor advisory and patch commit references. Rebuild container images and pin the fixed version in requirements.txt, pyproject.toml, or equivalent dependency manifests.

Workarounds

Avoid using GitPython's config write APIs on configuration files sourced from untrusted repositories
Run GitPython automation under least-privilege service accounts with no interactive shell access
Set GIT_CONFIG_NOSYSTEM=1 and use core.hooksPath overrides pointing to a read-only, vetted directory
Validate repository config files for embedded newlines in quoted values before any GitPython write operation

bash

# Configuration example
pip install --upgrade 'GitPython>=3.1.59'
pip show GitPython | grep -i version