How severe is CVE-2020-27955?

CVE-2020-27955 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-27955?

CVE-2020-27955 affects the following packages: github.com/git-lfs/git-lfs (Go). Ecosystems affected: Go.

How do I fix CVE-2020-27955?

Update github.com/git-lfs/git-lfs to 2.12.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-27955 is resolved across your whole dependency graph.

How do I detect CVE-2020-27955 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-2020-27955 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-2020-27955 actively exploited in the wild?

Yes. There are 12 known exploit references for CVE-2020-27955, including 9 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2020-27955?

CVE-2020-27955 has an EPSS (Exploit Prediction Scoring System) score of 82.3%, placing it in the 100th 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. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2020-27955?

CVE-2020-27955 is classified as CWE-427 (CWE-427). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2020-27955?

A Metasploit module references CVE-2020-27955, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2020-27955 published, and has it been updated?

CVE-2020-27955 was published on November 5, 2020 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

CRITICAL severity

CVE-2020-27955 — git-lfs

CRITICAL

CVE-2020-27955 is a critical-severity (CVSS 9.8) CWE-427 vulnerability in github.com/git-lfs/git-lfs. 12 public exploit or proof-of-concept references are indexed, so weaponization risk is real. 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

Also known asBIT-git-lfs-2020-27955GHSA-4g4p-42wc-9f3m

Published

Nov 5, 2020

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

12 known

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

82.3%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% 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 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 v2.12.1, which will be released in coordination with this security advisory.

Workarounds

Other than avoiding untrusted repositories, there is no workaround.

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	2.12.1`go get github.com/git-lfs/git-lfs@v2.12.1`

Affected Products

1 product · 1 configurations

Application

git large file storagegit_large_file_storage_project

1 version

2.12.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Git LFS 2.12.0 allows Remote Code Execution.

legalhackers.comNVDJul 2021

Report on exploitbox.io

exploitbox.ioNVDJul 2021

Report on seclists.org

seclists.orgNVDJul 2021

Report on packetstormsecurity.com

packetstormsecurity.comNVDJul 2021

Report on github.com

github.comGithubNov 2020

Report on github.com

github.comGithubNov 2020

Report on github.com

github.comGithubNov 2020

Report on github.com

github.comMetasploitSep 2021

Report on packetstormsecurity.com

packetstormsecurity.comNVDDec 2021

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 2.12.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-27955 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 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 v2.12.1, which will be released in coordination with this security advisory. ### Workarounds Other than avoiding untrusted repositories, there is no wo

O3 Security · Impact-Aware SCA

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Find it across Go, including transitive dependencies.

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CVSS Score

9.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE Classification

Weaponization

OpenSSF Scorecard

Package health score

git-lfs

6.5/10

Code-Review10/10

Maintained10/10

Branch-ProtectionN/A

Assessed Oct 19, 2026

Timeline

Disclosed

Nov 5, 2020

First exploit

Jul 21, 2021

Last updated

Oct 20, 2026

Identifiers

CVE-2020-27955

GHSA-4g4p-42wc-9f3m

BIT-git-lfs-2020-27955

References

Advisorygithub.com · releases Advisorylegalhackers.com Advisorynvd.nist.gov · CVE 2020 27955 Webgithub.com · GHSA 4g4p 42wc 9f3m Packagegithub.com · git lfs Evidencepacketstormsecurity.com · git lfs Remote Code Execution Evidencepacketstormsecurity.com · Git git lfs Remote Code Execution Evidenceseclists.org Evidenceexploitbox.io Evidencelegalhackers.com · Git LFS RCE Exploit CVE 2020 27955

Related vulnerabilities

Also affects git-lfs

This CVE is critical severity; 1 of 5 other CVEs affecting git-lfs is rated as high or higher (top: critical).

CVE-2025-26625CVE-2024-53263CVE-2017-17831CVE-2022-24826CVE-2021-21237

Same weakness: CWE-427

This CVE is critical severity — higher than any of the other 3 CVEs with CWE-427 (highest there: high).

CVE-2026-62847CVE-2026-61446CVE-2026-86540Browse all CWE-427

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 20, 2026

CVE-2020-27955 — git-lfs

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Impact

Patches

Workarounds

For more information

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2020-27955 in your dependencies?