MalwarePublished 29 Oct 2025

only-warn (npm) · Malicious Code

Affects only-warnSource GCVE Database

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

Data as of 29 Oct 2026, 23:05 UTC

Classification

Malicious package

Published to npm · OSV MAL-2025-49028

What to do

Remove only-warn 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
npmonly-warn	Affected =9.9.0	Fixed in–

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Description

The npm package 'only-warn' version 9.9.0 contains malicious code that installs a dependency from a custom domain which executes an information stealer during installation. This malware targets sensitive tokens related to npm, git, and CI/CD environments. Any system with this package installed or running is considered fully compromised, necessitating immediate rotation of all secrets and keys from a secure machine. Removal of the package alone does not guarantee eradication of all malicious components.

Impact

Systems with 'only-warn' version 9.9.0 installed are fully compromised, risking exposure of all stored secrets and keys, including npm, git, and CI/CD tokens. This can lead to unauthorized access to development and deployment infrastructure, potentially enabling further malicious activity or data breaches.

Defensive guidance

Immediately remove the 'only-warn' package version 9.9.0 from all affected systems. Rotate all secrets, keys, and tokens from a secure, uncompromised machine. Treat affected systems as fully compromised and consider rebuilding or thoroughly auditing them to ensure no persistent malicious components remain.

Summary

The 'only-warn' npm package at version 9.9.0 includes a malicious dependency hosted on a custom domain that executes an info stealer during the package installation process. This info stealer specifically targets npm, git, and CI/CD tokens, potentially allowing attackers to gain unauthorized access to these credentials. Due to the nature of the compromise, systems with this package installed should be treated as fully compromised, and all secrets should be rotated from a different, secure system. The package removal is insufficient to ensure full remediation as the attacker may have established persistent control.

References

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What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Oct 2026, 23:05 UTC

Technical details

References

Community reviews