MAL-2026-5739 Malicious code in sheratan_haha (npm)
Malicious package
Published
MAL-2026-5739 is a malicious package: sheratan_haha (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-2026-5739/ (Markdown: https://insights.sbomify.com/MAL-2026-5739/index.md)
- Package
- sheratan_haha
- Registry
- npm
What is MAL-2026-5739?
MAL-2026-5739 is a malicious package in sheratan_haha, published on 13 Jun 2026.
Official description
On
npm install, the package's declared postinstall hook (node postinstall.js) runs whoami on the installer's machine and POSTs the output to a hardcoded webhook.site endpoint (https://webhook.site/0ea9eb45-3ede-4cf0-9ea9-2b8d700272e7) via https.request. The package advertises itself as 'A simple date formatting utility' but ships no library code consistent with that purpose — the only behavior on install is host fingerprinting and exfiltration to an attacker-controlled URL. Metadata is placeholder-shaped (empty author, generic description, name sheratan_haha), consistent with a dependency-confusion / recon PoC. Installing this package leaks the installer's OS username to an external endpoint controlled by the publisher.What should I do about MAL-2026-5739?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.