# CVE-2026-25143: melange affected by potential host command execution via license-check YAML mode patch pipeline

> Attackers can execute arbitrary shell commands on the build host by injecting metacharacters into melange patch pipeline inputs.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Feb 2026
- **Updated:** 5 Feb 2026
- **Also known as:** GHSA-rf4g-89h5-crcr, GO-2026-4412

## What is CVE-2026-25143?

CVE-2026-25143 is a high-severity command injection vulnerability in chainguard-dev melange, published on 4 Feb 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

melange allows users to build apk packages using declarative pipelines. From version 0.10.0 to before 0.40.3, an attacker who can influence inputs to the patch pipeline could execute arbitrary shell commands on the build host. The patch pipeline in pkg/build/pipelines/patch.yaml embeds input-derived values (series paths, patch filenames, and numeric parameters) into shell scripts without proper quoting or validation, allowing shell metacharacters to break out of their intended context. The vulnerability affects the built-in patch pipeline which can be invoked through melange build and melange license-check operations. An attacker who can control patch-related inputs (e.g., through pull request-driven CI, build-as-a-service, or by influencing melange configurations) can inject shell metacharacters such as backticks, command substitutions $(…), semicolons, pipes, or redirections to execute arbitrary commands with the privileges of the melange build process. This issue has been patched in version 0.40.3.

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

## Which versions are affected by CVE-2026-25143?

3 open source packages ship an affected version, including chainguard.dev/melange. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `chainguard.dev/melange` | Go | From 0.10.0 | 0.40.3 |
| `chainguard.dev/melange` | Go | From 0.10.0 | 0.40.3 |
| `chainguard.dev/melange` | Go | From 0.10.0 | 0.40.3 |

Products: Chainguard Melange.

## How do I fix CVE-2026-25143?

Upgrade chainguard.dev/melange to 0.40.3 or later.

## Is CVE-2026-25143 being exploited?

There is no known exploitation of CVE-2026-25143 in the wild and no public exploit code.

## Other vulnerabilities in chainguard-dev melange

- [CVE-2026-24843](https://insights.sbomify.com/CVE-2026-24843/): melange QEMU runner could write files outside workspace directory (high 8.2)
- [CVE-2026-24844](https://insights.sbomify.com/CVE-2026-24844/): melange pipeline working-directory could allow command injection (high 7.8)
- [CVE-2026-29050](https://insights.sbomify.com/CVE-2026-29050/): melange has Path Traversal When Resolving External Pipelines via Unvalidated pipeline[].uses (medium 6.1)
- [CVE-2026-25145](https://insights.sbomify.com/CVE-2026-25145/): melange has a path traversal in license-path which allows reading files outside workspace (medium 5.5)
- [CVE-2026-29051](https://insights.sbomify.com/CVE-2026-29051/): melange has Path Traversal via .PKGINFO in --persist-lint-results (medium 4.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25143 and fix it if it is affected.

What it is: CVE-2026-25143 is a high-severity command injection vulnerability in chainguard-dev melange, published on 4 Feb 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-25143 in the wild and no public exploit code.

Affected packages and fixed versions:
- chainguard.dev/melange (Go): affected from 0.10.0; fixed in 0.40.3
- chainguard.dev/melange (Go): affected from 0.10.0; fixed in 0.40.3
- chainguard.dev/melange (Go): affected from 0.10.0; fixed in 0.40.3

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-2026-25143/ (Markdown: https://insights.sbomify.com/CVE-2026-25143/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25143
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25143
- OSV: https://osv.dev/vulnerability/CVE-2026-25143

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25143/
Summaries are generated and may contain mistakes; the official description above is the record.