How severe is CVE-2021-21237?

CVE-2021-21237 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-21237?

CVE-2021-21237 affects the following packages: github.com/git-lfs/git-lfs (Go). Ecosystems affected: Go.

How do I fix CVE-2021-21237?

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.

How do I detect CVE-2021-21237 in my Go dependencies?

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.

How do I mitigate CVE-2021-21237 if there is no patch (or I can't update yet)?

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.

Is CVE-2021-21237 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-21237 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-21237?

CVE-2021-21237 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 40th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-21237?

CVE-2021-21237 is classified as CWE-426 (CWE-426). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-21237 published, and has it been updated?

CVE-2021-21237 was published on January 15, 2021 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

HIGH severity

CVE-2021-21237 — git-lfs

HIGHFix: git-lfs/git-lfs@fc66469

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

Also known asBIT-git-lfs-2021-21237GHSA-cx3w-xqmc-84g5GO-2021-0098

Published

Jan 15, 2021

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs40th percentile — riskier than 40% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐹github.com/git-lfs/git-lfs

Real-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

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/git-lfs/git-lfs`	all versions	2.13.2`go get github.com/git-lfs/git-lfs@v2.13.2`

Affected Products

1 product · 1 configurations

Application

git large file storagegit_large_file_storage_project

< 2.13.2

range

Detection & mitigation playbook

Open-source dependency

Detect
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.

Frequently Asked Questions

### 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](https://github.com/golang/go/issues/38736). ### Patches This version should be patched in v2.13.2, which will be released in coordinati