Critical Malicious Code Vulnerability in stylus.js Package
Summary
MAL-2026-542: Malicious code in stylus.js (npm). Affected versions are not published. No fix is published. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
stylus.js is a popular package in the npm ecosystem used for CSS pre-processing, allowing developers to write styles in a more dynamic and maintainable way. It offers features like variables, nesting, and mixins, making it a preferred choice for many web developers. However, the package has been compromised, introducing malicious code that poses significant security risks to any system using it.
Vulnerability Detail
The vulnerability stems from the presence of embedded malicious code within the stylus.js package. This code can fully compromise any computer that has the package installed, potentially allowing unauthorized access to sensitive information such as secrets and keys. The malicious nature of the code was identified by the GHSA malware source, indicating that the package should be treated as a severe threat. Users are advised to consider their systems compromised and take immediate action to mitigate risks.
How To Fix
This package is malicious. Remove it and rotate any credentials it could have accessed.
npm uninstall stylus.jsIf it arrived as a transitive dependency, remove the package that pulled it in, then reinstall.
Tip — Not sure whether your app is affected? Vulert can check the versions your app actually runs. Scan free →
Workaround
As a workaround, it is recommended to rotate all secrets and keys stored on the affected computer from a different, secure machine. This will help mitigate the risks associated with the potential exposure of sensitive information.
Conclusion
The stylus.js package has been identified as containing malicious code, posing a significant security threat to any systems using it. Immediate action is required to remove the package and secure sensitive information. Users are encouraged to utilize tools like Vulert for ongoing monitoring of vulnerabilities in their applications.
See every vulnerability recorded for stylus.js →
FAQ
The malicious code is designed to compromise the security of the system, potentially allowing unauthorized access to sensitive information.
You can use Vulert's playground at Vulert Scanner to check if your application is affected without needing to sign up.
Immediately remove the stylus.js package from your project and rotate any sensitive information stored on the affected system.
Currently, there is no patched version available. Users should focus on removing the package and securing their systems.
Vulert monitors and alerts users in real-time for open-source vulnerabilities using just the package-lock.json file, ensuring that you stay informed about potential threats.
