CVE-2021-21237 is a high-severity (CVSS 7.8) CWE-426 vulnerability in github.com/git-lfs/git-lfs. A fix is available for github.com/git-lfs/git-lfs — see the affected versions and patch details below.
Git LFS can execute a Git binary from the current directory on Windows
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
CVE-2021-21237 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 378,567 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
github.com/git-lfs/git-lfsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
On Windows, if Git LFS operates on a malicious repository with a git.bat or git.exe file in the current directory, that program would be executed, permitting the attacker to execute arbitrary code. This does not affect Unix systems.
This is the result of an incomplete fix for CVE-2020-27955.
This issue occurs because on Windows, Go includes (and prefers) the current directory when the name of a command run does not contain a directory separator.
Patches
This version should be patched in v2.13.2, which will be released in coordination with this security advisory.
Workarounds
Other than avoiding untrusted repositories or using a different operating system, there is no workaround.
References
Are there any links users can visit to find out more?
For more information
If you have any questions or comments about this advisory:
- Start a discussion in the Git LFS discussion page.
- If you cannot open a discussion, please email the core team using their usernames at
github.com.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/git-lfs/git-lfs | all versions | 2.13.2go get github.com/git-lfs/git-lfs@v2.13.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/git-lfs/git-lfs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/git-lfs/git-lfs to 2.13.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21237 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 CVE-2021-21237 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2021-21237. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-21237 in your dependencies?
O3 Security finds CVE-2021-21237 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.