# CVE-2023-31128: NextCloud Cookbook's pull-checks.yml workflow is vulnerable to OS Command Injection

> Attackers can execute arbitrary commands in the repository's CI/CD pipeline via untrusted input in the pull-checks workflow.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 May 2023
- **Updated:** 14 Jan 2025
- **Also known as:** GHSA-c5pc-mf2f-xq8h

## What is CVE-2023-31128?

CVE-2023-31128 is a high-severity command injection vulnerability in nextcloud cookbook, published on 26 May 2023. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

NextCloud Cookbook is a recipe library app. Prior to commit a46d9855 on the `master` branch and commit 489bb744 on the `main-0.9.x` branch, the `pull-checks.yml` workflow is vulnerable to command injection attacks because of using an untrusted `github.head_ref` field. The `github.head_ref` value is an attacker-controlled value. Assigning the value to `zzz";echo${IFS}"hello";#` can lead to command injection. Since the permission is not restricted, the attacker has a write-access to the repository. This issue is fixed in commit a46d9855 on the `master` branch and commit 489bb744 on the `main-0.9.x` branch. There is no risk for the user of the app within the NextCloud server. This only affects the main repository and possible forks of it. Those who have forked the NextCloud Cookbook repository should make sure their forks are on the latest version to prevent code injection attacks and similar.

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

## Which versions are affected by CVE-2023-31128?

It affects 1 product.


Products: Nextcloud Cookbook.

## How do I fix CVE-2023-31128?

No fix has been published for CVE-2023-31128 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-31128 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-31128 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-31128 and fix it if it is affected.

What it is: CVE-2023-31128 is a high-severity command injection vulnerability in nextcloud cookbook, published on 26 May 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-31128 exists.

Affected product: nextcloud cookbook. 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-2023-31128/ (Markdown: https://insights.sbomify.com/CVE-2023-31128/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-31128
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-31128
- OSV: https://osv.dev/vulnerability/CVE-2023-31128

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-31128/
Summaries are generated and may contain mistakes; the official description above is the record.