OpenSSF/OSV advisory MAL-2026-4524 confirms this npm version as malicious. 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`...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in claude-content-writer (npm)
Details
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.
Decision reason
OpenSSF Malicious Packages via OSV confirms claude-content-writer@2.2.0 as malicious (MAL-2026-4524): Malicious code in claude-content-writer (npm)