Malicious Code Detected in ac-checksum Package - Security Alert

ac-checksum Updated 06 Feb 2026

Summary

06/02/2026
CRITICAL
No i
Critical
Not published

MAL-2026-776: Malicious code in ac-checksum (npm). Affected versions are not published. No fix is published. How to fix ↓

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Background

The ac-checksum package is a utility in the npm ecosystem that is typically used for generating checksums for data integrity verification. It is designed to help developers ensure that files have not been altered or corrupted. However, this package has been identified as containing malicious code, which poses significant security risks to applications that rely on it.

Vulnerability Detail

The vulnerability in the ac-checksum package stems from the presence of malicious code that can compromise the integrity and security of applications using it. This code was discovered through an analysis by Amazon Inspector, which flagged the package for containing harmful elements. The ramifications of this vulnerability include potential data breaches, unauthorized access to sensitive information, and the risk of further exploitation within the application environment.

How To Fix

This package is malicious. Remove it and rotate any credentials it could have accessed.

npm uninstall ac-checksum

If 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

If an immediate update is not feasible, consider removing the ac-checksum package from your project until a secure version is released. You can do this by executing: 'npm uninstall ac-checksum'. This will help prevent any potential exploitation of the malicious code.

Conclusion

The ac-checksum package has been flagged for containing malicious code, posing significant security risks to applications. It is essential to update or remove the package to safeguard your application from potential threats. Utilizing tools like Vulert can help you stay informed about vulnerabilities in your dependencies.

See every vulnerability recorded for ac-checksum →

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FAQ

The ac-checksum package is used for generating checksums to verify the integrity of files in applications.

The malicious code was identified through an analysis conducted by Amazon Inspector, which monitors open-source packages for security vulnerabilities.

Using the compromised package can lead to data breaches, unauthorized access, and exploitation of your application.

You can use the Vulert platform to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected without needing to sign up.

If an immediate update is not possible, consider uninstalling the ac-checksum package to prevent any exploitation of the malicious code.

How To Fix

This package is malicious. Remove it and rotate any credentials it could have accessed.

npm uninstall ac-checksum

If 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 →

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