# MAL-2026-4638: Malicious code in pewter-constantstest (npm)


- **Type:** Malicious package
- **Package:** `pewter-constantstest` (npm)
- **Published:** 23 May 2026

## What is MAL-2026-4638?

MAL-2026-4638 is a malicious package in pewter-constantstest, published on 23 May 2026. 

### Official description

On `npm install`, the `preinstall` script `callback.js` collects the installer's hostname, OS username, current working directory, npm registry configuration, and CI repository identifiers from a broad list of CI environment variables (GITHUB_REPOSITORY, CI_PROJECT_PATH, BUILD_REPOSITORY_NAME, BITBUCKET_REPO_FULL_NAME, TRAVIS_REPO_SLUG, DRONE_REPO, BUILDKITE_PIPELINE_SLUG, CIRCLE_PROJECT_REPONAME, JOB_NAME) and transmits them via plaintext HTTP GET to the hardcoded bare IP `http://75.119.137.232:31337/depconfuse`. The package has no functional surface: `index.js` exports an empty object, the description is the generic `Shared utility helpers.`, the README is 48 bytes, and the version is `9999.0.0` — the canonical dependency-confusion override version designed to win resolution against an internal package of the same name. The package exists solely to fire the beacon when an organization accidentally resolves this public name in place of a private/internal package, leaking the victim's identity and internal repo names to the attacker for follow-on targeting.

## What should I do about MAL-2026-4638?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-4638 is a malicious package: pewter-constantstest (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-4638/ (Markdown: https://insights.sbomify.com/MAL-2026-4638/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4638

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-4638/
Summaries are generated and may contain mistakes; the official description above is the record.