MalwarePublished 26 Jun 2026

@merceas/cross-fetch (npm) · Malicious Code

Affects @merceas/cross-fetchSource GCVE Database

Malicious package : remove @merceas/cross-fetch 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-2026-6510

What to do

Remove @merceas/cross-fetch 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
npm@merceas/cross-fetch	Affected =3.1.12	Fixed in–

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Description

The @merceas/cross-fetch npm package version 3.1.12 is a malicious package impersonating the legitimate cross-fetch library. It contains obfuscated code that, when imported, downloads and executes attacker-controlled payloads on the host machine. This execution occurs in any environment that loads the module, including CI, build, production, or developer workstations, enabling remote code execution and persistence.

Impact

This malicious package enables remote code execution on any system that imports it, potentially compromising build environments, continuous integration pipelines, production systems, or developer machines. The attacker-controlled payload can execute arbitrary commands with the privileges of the importing process, leading to full system compromise, persistence, and further malicious activity. There are no known exploits in the wild reported at this time.

Defensive guidance

Users and organizations should immediately remove the @merceas/cross-fetch package version 3.1.12 from their projects and dependency trees. Verify that no transitive dependencies are pulling in this package. Use trusted sources and verify package authenticity before installation. Monitor for any unusual activity on affected systems and consider rebuilding environments after removal.

Summary

The malicious @merceas/cross-fetch package (version 3.1.12) masquerades as the legitimate cross-fetch npm package by reusing its README, homepage, and author metadata. Its main module includes decoy code plus obfuscated Immediately Invoked Function Expressions (IIFEs) that dynamically import Node.js core modules to decrypt a URL, fetch a payload via HTTPS with retry and redirect handling, write the payload to a temporary directory, set executable permissions, and execute it via bash. It also spawns a detached child process for persistence. The obfuscation techniques include string-array numeric shifts, RC4-keyed base64 lookups, and anti-tamper debugger self-tests to evade static analysis. Importing this package results in execution of attacker-controlled code on the host.

References

npmjs.com/package/@merceas/cross-fetch/v/3.1.12 (opens in a new tab)

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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