{"schema_version":"1.9.0","id":"GHSA-9rj7-rf2p-w77r","published":"2026-08-07T15:36:43Z","modified":"2026-09-10T12:25:55.324487522Z","aliases":["CVE-2026-76218","PYSEC-2026-3840"],"summary":"GitPython: Unguarded git option forwarding in Repo.init enables arbitrary command execution via --template clone hooks","details":"## Summary\n`Repo.init()` forwards `**kwargs` verbatim to `git init` with no unsafe-option guard and no `allow_unsafe_options` parameter. `git init --template=<dir>` copies `<dir>/hooks/*` into the new repo's `.git/hooks`, so an attacker-controlled `template` kwarg plants a hook that executes on the next git operation → arbitrary code execution. `--template` is already recognized as unsafe for clone (it is on `unsafe_git_clone_options`, and GHSA-6p8h-3wgx-97gf covers the clone path), but `Repo.init` is a distinct method that never received a guard and needs an independent fix.\n\n## Root Cause\n`Repo.init(path, mkdir, odbt, expand_vars, **kwargs)` is a bare `git.init(**kwargs)` (git/repo/base.py:1435) with no `check_unsafe_options` and no `allow_unsafe_options`.\n\n## Impact\nArbitrary code execution (hook fires on next git op) at the privileges of the host process. Two preconditions raise attack complexity (AC:H): the app must forward a `template=` kwarg (KEY control) AND the attacker must stage an executable hook directory at a known path — the same profile GHSA-6p8h-3wgx-97gf accepted as HIGH for the clone path. Default `allow_unsafe_options` is irrelevant here because `Repo.init` has no guard at all.\n\n## Proof of Concept\n```python\n# attacker stages /evil/hooks/post-commit (executable)\nfrom git import Repo\nRepo.init(path, template=\"/evil\")\n# next commit runs /evil/hooks/post-commit -> ACE\n```\n\n## Attack Chain\n1. Entry: attacker stages `/evil/hooks/post-commit` (executable) and gets the app to call `Repo.init(path, template='/evil')`.\n2. Check: NONE on `Repo.init`. Bypass proof: base.py:1435 is a bare `git.init(**kwargs)`. argv (observed): `['git','init','--template=/evil']`.\n3. Sink: git copies `/evil/hooks/post-commit` → `<repo>/.git/hooks/post-commit`.\n4. Impact: next commit runs the hook → arbitrary code execution.\n\n## Bypass Evidence\nIndependently reproduced (gate harness): `Repo.init(dst, template='<evil>')` → argv `['git','init','--template=<evil>']` unguarded; hook copied into `.git/hooks/post-commit`; after `git commit` the `INIT_ACE` marker was created. `--separate-git-dir=<path>` is a parallel arbitrary-redirect vector through the same unguarded sink (value control only).\n\n## Affected Versions\n`GitPython <= 3.1.57` (unguarded `git.init(**kwargs)` present verbatim on the latest release tag).\n\n## Suggested Fix\nAdd a `check_unsafe_options` guard (with an `allow_unsafe_options` parameter) to `Repo.init`, consulting a denylist that includes `--template` and `--separate-git-dir` (path-taking / hook-installing options).\n\n---\nReported by **zx (Jace)** — GitHub: @manus-use","affected":[{"package":{"name":"gitpython","ecosystem":"PyPI","purl":"pkg:pypi/gitpython"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.58"}]}],"versions":["0.1.7","0.2.0-beta1","0.3.0-beta1","0.3.0-beta2","0.3.1-beta2","0.3.2","0.3.2.1","0.3.2.RC1","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","1.0.0","1.0.1","1.0.2","2.0.0","2.0.1","2.0.2","2.0.3","2.0.4","2.0.5","2.0.6","2.0.7","2.0.8","2.0.9","2.0.9.dev0","2.0.9.dev1","2.1.0","2.1.1","2.1.10","2.1.11","2.1.12","2.1.13","2.1.14","2.1.15","2.1.2","2.1.3","2.1.4","2.1.5","2.1.6","2.1.7","2.1.8","2.1.9","3.0.0","3.0.1","3.0.2","3.0.3","3.0.4","3.0.5","3.0.6","3.0.7","3.0.8","3.0.9","3.1.0","3.1.1","3.1.10","3.1.11","3.1.12","3.1.13","3.1.14","3.1.15","3.1.16","3.1.17","3.1.18","3.1.19","3.1.2","3.1.20","3.1.22","3.1.23","3.1.24","3.1.25","3.1.26","3.1.27","3.1.28","3.1.29","3.1.3","3.1.30","3.1.31","3.1.32","3.1.33","3.1.34","3.1.35","3.1.36","3.1.37","3.1.38","3.1.4","3.1.40","3.1.41","3.1.42","3.1.43","3.1.44","3.1.45","3.1.46","3.1.47","3.1.48","3.1.49","3.1.5","3.1.50","3.1.51","3.1.52","3.1.53","3.1.54","3.1.55","3.1.56","3.1.57","3.1.6","3.1.7","3.1.8","3.1.9"],"database_specific":{"last_known_affected_version_range":"<= 3.1.57","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-9rj7-rf2p-w77r/GHSA-9rj7-rf2p-w77r.json"}}],"references":[{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-9rj7-rf2p-w77r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-76218"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/pull/2204"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/commit/d9ddb55bdc66"},{"type":"PACKAGE","url":"https://github.com/gitpython-developers/GitPython"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/releases/tag/3.1.58"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/gitpython-before-remote-code-execution-via-repo-init"}],"database_specific":{"cwe_ids":["CWE-88","CWE-94"],"github_reviewed":true,"github_reviewed_at":"2026-08-07T15:36:43Z","nvd_published_at":null,"severity":"HIGH"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}