# MAL-2026-6353: Malicious code in markdownlint-cli2-fix (npm)


- **Type:** Malicious package
- **Package:** `markdownlint-cli2-fix` (npm)
- **Published:** 23 Jun 2026
- **Also known as:** GHSA-75g7-vcxw-p99c

## What is MAL-2026-6353?

MAL-2026-6353 is a malicious package in markdownlint-cli2-fix, published on 23 Jun 2026. 

### Official description

Package name 'markdownlint-cli2-fix' impersonates the popular 'markdownlint-cli2' linter but contains no linter functionality — the README states 'Takeover By lobo / For POC only' and the package ships only postinstall.js plus metadata. postinstall.js (line 30) hardcodes `BURP_COLLABORATOR_URL = "http://i0jvc03bvcjt40q39f5fx8671y72vxjm.oastify.com"` and, when run, collects host/network reconnaissance (os.hostname(), username, network interfaces, disk info, AD domain info, full process list via `ps aux`/`tasklist` through execSync), enumerates `Object.keys(process.env)` matching a curated credential list (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, GITHUB_TOKEN, NPM_TOKEN, STRIPE_SECRET, SSH_PRIVATE_KEY, DEPLOY_KEY, SLACK_TOKEN, DISCORD_TOKEN, JWT_SECRET) plus regex `/_(TOKEN|SECRET|KEY|PASSWORD|PWD|APIKEY|API_KEY|PRIVATE_KEY)$/i`, and POSTs the JSON payload to the attacker-controlled Burp Collaborator endpoint at oastify.com. While package.json in this version does not declare a `scripts.postinstall` hook (so the file does not auto-execute on `npm install`), the package is a deliberate typosquat with no legitimate purpose, the exfiltration code is fully functional, and any installer who is tricked into running the file — or any republish that wires the lifecycle hook — produces immediate credential exfiltration.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-6353?

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-2026-6353 is a malicious package: markdownlint-cli2-fix (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-2026-6353/ (Markdown: https://insights.sbomify.com/MAL-2026-6353/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6353

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-6353/
Summaries are generated and may contain mistakes; the official description above is the record.