GitPython: Arbitrary file truncation via git rev-list --output argument injection in unguarded Commit.count
Summary
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=<path> opens and truncates the target file to 0 bytes before revision parsing, so count(output='/victim') destroys/blanks an arbitrary file.
Root Cause
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.
Impact
Destroy/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.
Proof of Concept
commit.count(output='/path/to/victim') # victim truncated to 0 bytes (verified)
# control: commit.iter_commits(output=...) raises UnsafeOptionErrorAttack Chain
- Entry: app forwards user options ->
commit.count(output='/victim'). Guard: none. Bypass proof:iter_commits(output=)raises UnsafeOptionError;count(output=)does not — verified side-by-side. - Sink:
git rev-list <sha> --output=/victim-> file truncated to 0 bytes. Impact: destroy/blank arbitrary file.
Bypass Evidence
Live-verified on HEAD (tag 3.1.53): count(output=<victim>) 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.
Affected Versions
<= 3.1.53
Suggested Fix
Add check_unsafe_options to Commit.count (mirroring iter_items).
Reported by zx (Jace) — GitHub: @manus-use
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | gitpython | < 3.1.56 | 3.1.56 |
References
- https://www.vulncheck.com/advisories/gitpython-before-arbitrary-file-truncation-via-commit-count
- https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-p538-c434-8v24
- https://github.com/gitpython-developers/GitPython/pull/2184
- https://github.com/gitpython-developers/GitPython/commit/38553b6fddc7f6a667cdb45a6762343a08fc72b2
- https://github.com/gitpython-developers/GitPython
- https://github.com/gitpython-developers/GitPython/releases/tag/3.1.56
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L- Weakness (CWE)
CWE-88- Platform
- Python (PyPI)
- Package
gitpython- Disclosed
- 03.08.2026
- Updated
- 11.10.2026 15:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3950 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-p538-c434-8v24 - CC BY 4.0
Vulnerability history: gitpython
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 37
- First → latest
- 12.2022 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 3
- High 26
- Medium 8
Disclosures per year
- 2022: 1
- 2023: 3
- 2024: 1
- 2025: 0
- 2026: 32
-
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