{"id":"GHSA-p538-c434-8v24","summary":"GitPython: Arbitrary file truncation via git rev-list --output argument injection in unguarded Commit.count","details":"## Summary\n`Commit.count()` forwards `**kwargs` into `rev_list` with **no** `check_unsafe_options` guard (the guard exists only in the sibling `iter_items`, commit.py:341). `git rev-list --output=\u003cpath\u003e` opens and truncates the target file to 0 bytes before revision parsing, so `count(output='/victim')` destroys/blanks an arbitrary file.\n\n## Root Cause\n`commit.py:290-291` calls `self.repo.git.rev_list(self.hexsha, **kwargs)` with no `check_unsafe_options` and no `allow_unsafe_options` parameter. The sibling `iter_items` (commit.py:341) is guarded; `count` is not. This is a distinct, uncovered sink — GHSA-956x-8gvw-wg5v fixed `iter_commits`/`blame`, not `count`.\n\n## Impact\nDestroy/blank an arbitrary file at process privilege (integrity/availability). Reachability is key-control only (`count` uses `self.hexsha`, not a user ref), and the write is a 0-byte truncation (no content control), so MEDIUM.\n\n## Proof of Concept\n```python\ncommit.count(output='/path/to/victim')   # victim truncated to 0 bytes (verified)\n# control: commit.iter_commits(output=...) raises UnsafeOptionError\n```\n\n## Attack Chain\n1. Entry: app forwards user options -\u003e `commit.count(output='/victim')`. Guard: none. Bypass proof: `iter_commits(output=)` raises UnsafeOptionError; `count(output=)` does not — verified side-by-side.\n2. Sink: `git rev-list \u003csha\u003e --output=/victim` -\u003e file truncated to 0 bytes. Impact: destroy/blank arbitrary file.\n\n## Bypass Evidence\nLive-verified on HEAD (tag 3.1.53): `count(output=\u003cvictim\u003e)` truncated a pre-existing file to 0 bytes; guarded `iter_commits(output=)` raised UnsafeOptionError. Same CNA-accepted \"app forwards user options dict\" model as GHSA-956x-8gvw-wg5v's `archive(**kwargs)`. Uncovered sink, not a duplicate.\n\n## Affected Versions\n`\u003c= 3.1.53`\n\n## Suggested Fix\nAdd `check_unsafe_options` to `Commit.count` (mirroring `iter_items`).\n\n---\nReported by **zx (Jace)** — GitHub: @manus-use","aliases":["CVE-2026-73621","PYSEC-2026-3950"],"modified":"2026-09-10T13:10:53.755464477Z","published":"2026-08-03T20:23:17Z","database_specific":{"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-08-03T20:23:17Z","nvd_published_at":null,"cwe_ids":["CWE-88"]},"references":[{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-p538-c434-8v24"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/pull/2184"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/commit/38553b6fddc7f6a667cdb45a6762343a08fc72b2"},{"type":"PACKAGE","url":"https://github.com/gitpython-developers/GitPython"},{"type":"WEB","url":"https://github.com/gitpython-developers/GitPython/releases/tag/3.1.56"}],"affected":[{"package":{"name":"gitpython","ecosystem":"PyPI","purl":"pkg:pypi/gitpython"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.56"}]}],"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","3.1.6","3.1.7","3.1.8","3.1.9"],"database_specific":{"last_known_affected_version_range":"\u003c= 3.1.55","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-p538-c434-8v24/GHSA-p538-c434-8v24.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L"}]}