GHSA-m4ch-rfv5-x5g3 is a medium-severity (CVSS 6.8) CWE-347 vulnerability in libgit2-sys. A fix is available for libgit2-sys — see the affected versions and patch details below.
git2-rs fails to verify SSH keys by default
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-m4ch-rfv5-x5g3.
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-m4ch-rfv5-x5g3 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 379,145 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
libgit2-sys🦀libgit2-sys🦀git2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
The git2 and libgit2-sys crates are Rust wrappers around the libgit2 C library. It was discovered that libgit2 1.5.0 and below did not verify SSH host keys when establishing an SSH connection, exposing users of the library to Man-In-the-Middle attacks.
The libgit2 team assigned CVE-2023-22742 to this vulnerability. The following versions of the libgit2-sys Rust crate have been released:
- libgit2-sys 0.14.2, updating the underlying libgit2 C library to version 1.5.1.
- libgit2-sys 0.13.5, updating the underlying libgit2 C library to version 1.4.5.
A new git2 crate version has also been released, 0.16.1. This version only bumps its libgit2-sys dependency to ensure no vulnerable libgit2-sys versions are used, but contains no code changes: if you update the libgit2-sys version there is no need to also update the git2 crate version.
You can learn more about this vulnerability in libgit2's advisory
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | libgit2-sys | ≥ 0.14.0&&< 0.14.2 | 0.14.2cargo update -p libgit2-sys --precise 0.14.2 |
| 🦀crates.io | libgit2-sys | all versions | 0.13.5cargo update -p libgit2-sys --precise 0.13.5 |
| 🦀crates.io | git2 | all versions | 0.16.1cargo update -p git2 --precise 0.16.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for libgit2-sys, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update libgit2-sys to 0.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m4ch-rfv5-x5g3 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-m4ch-rfv5-x5g3 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-m4ch-rfv5-x5g3. 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.
Frequently Asked Questions
Is GHSA-m4ch-rfv5-x5g3 in your dependencies?
O3 Security finds GHSA-m4ch-rfv5-x5g3 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.