MalwarePublished 29 Jun 2026Updated 30 Jul 2026

poly-kelly (npm) · Malicious Code

Affects poly-kellySource GCVE Database

Malicious package : remove poly-kelly and rotate any secrets on hosts that installed it.

Data as of 30 Jul 2026, 09:20 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-6584

What to do

Remove poly-kelly from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.

Affected software

Product	Affected	Fixed in
npmpoly-kelly	Affected =3.5.3	Fixed in–

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Description

The npm package 'poly-kelly' version 3.5.3 contains malicious code that executes during installation. Its postinstall script fetches a JSON configuration from a remote URL, downloads and extracts a tarball containing additional code, installs dependencies, and executes a function from the downloaded code. This process lacks integrity checks, allowing arbitrary JavaScript to run on the installer's machine. The package metadata is suspicious, lacking author and repository information, and uses the homepage field as a command-and-control configuration endpoint. Any system with this package installed should be considered fully compromised.

Impact

Installation of 'poly-kelly' version 3.5.3 results in arbitrary remote code execution on the installer's machine. This compromises the entire system, potentially exposing all stored secrets and keys. The attacker gains full control, and removing the package does not guarantee removal of all malicious artifacts. Systems with this package installed should be treated as fully compromised.

Defensive guidance

Remove the 'poly-kelly' package version 3.5.3 immediately from all affected systems. Rotate all secrets and keys from a separate, trusted machine. Because the package grants full control to an attacker, assume full system compromise and perform a thorough incident response.

Summary

The 'poly-kelly' npm package version 3.5.3 includes a postinstall script that reads a remote JSON configuration from a URL specified in the package.json homepage field. It downloads a tarball from this configuration, extracts it, installs its dependencies, and executes code from it without verifying integrity or authenticity. The remote URL can be overridden via environment variables and falls back from HTTPS to HTTP, enabling man-in-the-middle attacks to inject arbitrary code. The package's metadata is consistent with a disposable dropper, indicating intentional malicious behavior. This results in remote code execution on any machine installing this package.

References

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What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Jul 2026, 09:20 UTC

Technical details

References

Community reviews