MalwarePublished 16 Jun 2026Updated 26 Jun 2026

package-uploader (npm) · Malicious Code

Affects package-uploaderSource GCVE Database

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

Data as of 26 Jun 2026, 22:33 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-5932

What to do

Remove package-uploader 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
npmpackage-uploader	Affected =1.3.25	Fixed in–

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Description

The npm package 'package-uploader' version 1.3.25 contains malicious code that executes automatically during installation. It drops and runs an obfuscated Windows executable payload, then attempts to remove traces by editing package files and deleting its own directory. The package's declared functionality is a decoy unrelated to the malicious behavior. This supply-chain dropper compromises any system where it is installed, potentially giving full control to attackers.

Impact

Any computer with 'package-uploader' version 1.3.25 installed is likely fully compromised. The malicious payload runs automatically on installation, potentially allowing attackers full control over the system. All secrets and keys stored on the compromised machine should be considered exposed and must be rotated from a secure environment. Removing the package alone does not guarantee removal of all malicious components due to the persistence mechanisms and cleanup obfuscation.

Defensive guidance

The recommended mitigation is to immediately remove the 'package-uploader' package version 1.3.25 from all systems. Assume full compromise of affected systems and rotate all secrets and credentials from a secure, uncompromised environment. Monitor for any signs of persistence or additional malicious activity. Avoid installing or using this package or any variants with similar behavior.

Summary

The 'package-uploader' npm package at version 1.3.25 includes a postinstall script that runs 'install-hook.js'. This script contains a large base64-encoded binary payload that is XOR-decrypted and written as a temporary executable on Windows systems. The executable is launched detached, enabling execution of a hidden payload. After execution, a cleanup routine modifies package.json and package-lock.json to remove the dependency entry and deletes the installed module directory. If immediate deletion fails, it schedules a Windows task to remove the directory later. The package's stated purpose is a UI navbar library, but the main entry point only exports theme colors, serving as a decoy. The combination of obfuscated payload delivery, automatic execution, and anti-forensics cleanup confirms this as a supply-chain malware dropper. The campaign uses rotating package names, indicated by references to 'mailconfirmer' in cleanup code. Systems with this package installed should be considered fully compromised.

References

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What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Jun 2026, 22:33 UTC

Technical details

References

Community reviews