MAL-2026-3667 Malicious code in 0ctf-chalweb (npm)
Malicious package
Published
MAL-2026-3667 is a malicious package: 0ctf-chalweb (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-2026-3667/ (Markdown: https://insights.sbomify.com/MAL-2026-3667/index.md)
- Package
- 0ctf-chalweb
- Registry
- npm
What is MAL-2026-3667?
MAL-2026-3667 is a malicious package in 0ctf-chalweb, published on 12 May 2026.
Official description
The package's entire content (xss.js) is a 2-line cookie-stealing payload that creates an Image element pointing to https://collaborator.gbrls.workers.dev/ with base64-encoded document.cookie appended. This is a textbook XSS cookie exfiltration primitive targeting an attacker-controlled Cloudflare Workers endpoint. Regardless of whether this was published as a CTF artifact, any consumer who installs and bundles this package into a web app will exfiltrate end-users' cookies. There is no legitimate use case for publishing a cookie-exfil snippet to the public npm registry.
What should I do about MAL-2026-3667?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.