clsx-tailwindnpm
Advisory published Updated
clsx-tailwind is a confirmed malicious npm package (MAL-2026-5625) that executes malicious code on install (malicious version 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in clsx-tailwind (npm)
What this malware does
Package advertises a trivial Tailwind class-name merger (a 5-line cn() helper) but its main entry dist/index.js unconditionally requires dist/lib/lib.min.js, which runs at import time. That file (a) assigns require and module onto the global object so subsequently-evaluated code can resolve modules without containing literal require/module tokens, (b) reconstructs method names and an executable body via a hand-rolled string-shuffle decoder (YWG), and (c) resolves YWG[OSN] to Function.constructor and immediately invokes it on the decoded blob, evaluating obfuscated code on every consumer's require('clsx-tailwind'). The combination of heavy string-shuffle obfuscation, dynamic Function() evaluation of the decoded output, leaking require/module to the global namespace, and a payload entirely unrelated to the package's advertised purpose is the canonical malicious-payload shape. Any process that imports this package executes attacker-controlled code with the privileges of the host application.
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for clsx-tailwind (version 1.0.1).
If you installed it — respond
Remove clsx-tailwind from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If clsx-tailwind was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks clsx-tailwind-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.