# CVE-2021-29468: Arbitrary code execution when checking out an attacker-controlled Git branch

> Attackers can execute arbitrary code on Cygwin systems by tricking users into checking out a maliciously crafted Git repository containing specific symbolic links and filenames.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 29 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-rmp3-wq55-f557, OESA-2021-1210

## What is CVE-2021-29468?

CVE-2021-29468 is a high-severity code injection vulnerability in me-and Cygwin-Git, published on 29 Apr 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Cygwin Git is a patch set for the git command line tool for the cygwin environment. A specially crafted repository that contains symbolic links as well as files with backslash characters in the file name may cause just-checked out code to be executed while checking out a repository using Git on Cygwin. The problem will be patched in the Cygwin Git v2.31.1-2 release. At time of writing, the vulnerability is present in the upstream Git source code; any Cygwin user who compiles Git for themselves from upstream sources should manually apply a patch to mitigate the vulnerability. As mitigation users should not clone or pull from repositories from untrusted sources. CVE-2019-1354 was an equivalent vulnerability in Git for Visual Studio.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2021-29468?

It affects 1 product.


Products: Cygwin Git.

## How do I fix CVE-2021-29468?

Apply the vendor's patch.

## Is CVE-2021-29468 being exploited?

There is no known exploitation of CVE-2021-29468 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-29468 and fix it if it is affected.

What it is: CVE-2021-29468 is a high-severity code injection vulnerability in me-and Cygwin-Git, published on 29 Apr 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-29468 in the wild and no public exploit code.

Affected product: me-and Cygwin-Git. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-29468/ (Markdown: https://insights.sbomify.com/CVE-2021-29468/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-29468
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-29468
- OSV: https://osv.dev/vulnerability/CVE-2021-29468

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-29468/
Summaries are generated and may contain mistakes; the official description above is the record.