tailwindcss-mergenpm
tailwindcss-merge is a confirmed malicious npm package (MAL-2026-5632) that typosquats a legitimate package to trick installs (malicious versions 1.0.1, 1.0.2, 1.0.4). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in tailwindcss-merge (npm)
What this malware does
Package name tailwindcss-merge is a one-character edit of the popular tailwind-merge utility, and the README documents it as a drop-in (import {... } from 'tailwindcss-merge'). src/index.ts line 13 ends with a side-effect import import './lib/lib.min.js'; even though the manifest claims sideEffects: false. src/lib/lib.min.js is a heavily obfuscated bootstrap that (a) stashes require into global['r'] and module into global['m'], (b) uses a deterministic Knuth-style string-shuffle seeded with 2540575 to deshuffle the literal 'axhscuutcrogycrneotisjlnkdpfqmzovtrwb' into the string 'constructor', (c) dereferences that to obtain the Function constructor, and (d) deshuffles two further opaque blobs and executes them via Function('', decoded)(decoded2) followed by XZs(7942). The combination — typosquat name, side-effect import contradicting the manifest, capture of require/module into globals immediately before a two-stage opaque-string-to-Function eval chain — exists only to hide arbitrary code execution from review. Any consumer who imports this package (directly, or via the source field that bundlers like Parcel and Microbundle resolve to src/index.ts) executes the eval'd payload at module load with full access to require, enabling child-process spawn, network I/O, and filesystem reads. Manifest also points main at ./dist/bundle-cjs.js, but no dist/ directory ships in the tarball, and author is empty — publication-hygiene tells consistent with a hastily-assembled typosquat.
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
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for tailwindcss-merge (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging tailwindcss-merge across your stack and pipelines.
If you installed it — respond
tailwindcss-merge is a typosquat — you almost certainly intended a legitimately-named package. Remove tailwindcss-merge, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If tailwindcss-merge was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks tailwindcss-merge before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks tailwindcss-merge-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.