# CVE-2021-4281: Brave UX for-the-badge combine-prs.yml os command injection

> An attacker can execute arbitrary OS commands via the combine-prs.yml workflow in Brave UX for-the-badge, requiring a patch to mitigate.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Dec 2022
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-3796-3f93-cfvx

## What is CVE-2021-4281?

CVE-2021-4281 is a medium-severity command injection vulnerability in Brave UX for-the-badge, published on 26 Dec 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability was found in Brave UX for-the-badge and classified as critical. Affected by this issue is some unknown functionality of the file .github/workflows/combine-prs.yml. The manipulation leads to os command injection. The name of the patch is 55b5a234c0fab935df5fb08365bc8fe9c37cf46b. It is recommended to apply a patch to fix this issue. VDB-216842 is the identifier assigned to this vulnerability.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2021-4281?

It affects 1 product.


Products: Forthebadge for the Badge.

## How do I fix CVE-2021-4281?

No fix has been published for CVE-2021-4281 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-4281 being exploited?

There is no known exploitation of CVE-2021-4281 in the wild and no public exploit code.

Public exploit code:

- Security-research lab reproducing CVE-2021-4281 (GHSA-3796-3f93-cfvx): shell command injection via PR head-branch name in .github/workflows/combine-prs.yml (snapshot of BraveUX/for-the-badge @ 409c1fda). Do not use; authorized reproduction only. (github_poc): https://github.com/pvharmo2/gha-lab-232af4821f

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-4281 and fix it if it is affected.

What it is: CVE-2021-4281 is a medium-severity command injection vulnerability in Brave UX for-the-badge, published on 26 Dec 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-4281 in the wild and no public exploit code.

Affected product: Brave UX for-the-badge. 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-2021-4281/ (Markdown: https://insights.sbomify.com/CVE-2021-4281/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-4281
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-4281
- OSV: https://osv.dev/vulnerability/CVE-2021-4281

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-4281/
Summaries are generated and may contain mistakes; the official description above is the record.