# MAL-2026-4731: Malicious code in wml-core (npm)


- **Type:** Malicious package
- **Package:** `wml-core` (npm)
- **Published:** 25 May 2026

## What is MAL-2026-4731?

MAL-2026-4731 is a malicious package in wml-core, published on 25 May 2026. 

### Official description

wml-core@99.0.1 is a dependency-confusion package targeting an internal `wml-*` namespace, published with an inflated version (99.0.1) to win npm resolution against an internal package of the same name. The `preinstall` script `poc.js` runs automatically on `npm install` and harvests: hostname, username, OS/platform info, full network configuration (`ipconfig /all` on Windows or `ip a` + `/etc/resolv.conf` on Linux), `whoami /all` / `id` output, git remote URLs, the parent project's `package.json`, CI configuration files (`.gitlab-ci.yml`, `.github/workflows/*`, `Jenkinsfile`, `azure-pipelines.yml`), and a filtered dump of `process.env` matching credential-bearing prefixes including `TOKEN`, `AWS`, `AZURE`, `NPM`, `GITHUB`, `GITLAB`, `JENKINS`, `WALMART`, `WMT`, `CI_`. The collected JSON blob is POSTed to `d8a5d9pon5bugoc35cngp9hcregcqyezu.oast.me` (an Interactsh out-of-band callback host) over HTTPS, with a DNS callback emitted as a side channel. Any installer outside the intended target scope — including unintended internal builds and any third party who installs this name — has their build environment, CI secrets, and cloud/registry tokens exfiltrated. The package's self-description as 'authorized bug bounty research' does not change installer-side harm: the payload fires unconditionally on any `npm install`.

## What should I do about MAL-2026-4731?

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-2026-4731 is a malicious package: wml-core (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-2026-4731/ (Markdown: https://insights.sbomify.com/MAL-2026-4731/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4731

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-4731/
Summaries are generated and may contain mistakes; the official description above is the record.