MAL-2026-4524 Malicious code in claude-content-writer (npm)
Malicious package
Published
MAL-2026-4524 is a malicious package: claude-content-writer (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-2026-4524/ (Markdown: https://insights.sbomify.com/MAL-2026-4524/index.md)
- Package
- claude-content-writer
- Registry
- npm
What is MAL-2026-4524?
MAL-2026-4524 is a malicious package in claude-content-writer, published on 21 May 2026.
Official description
On
npm install, the package's postinstall hook runs scripts/install-dependencies.sh, which performs git clone --depth 1 https://github.com/AgriciDaniel/claude-seo.git and git clone of github.com/blader/humanizer into ~/.claude/skills with no commit pinning, then cd claude-seo && bash install.sh. The cloned repositories are personal GitHub accounts unrelated to the package publisher; whatever code their maintainers (or an attacker who takes over either account) push to HEAD will execute on every installer's machine at install time. There is no integrity verification, version pinning, or publisher-matching for the fetched code. Additionally, package.json declares the package itself as a dependency (claude-content-writer: ^2.0.1), which expands the install-time trust surface unpredictably by pulling another published version of the same package during resolution.What should I do about MAL-2026-4524?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.