tailwind-custom-formsnpm
tailwind-custom-forms is a confirmed malicious npm package (MAL-2026-12221) that opens a backdoor for remote access (malicious versions 0.5.0, 0.5.1, 0.5.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in tailwind-custom-forms (npm)
What this malware does
The package impersonates @tailwindcss/forms: package.json declares the name tailwind-custom-forms while the repository field points at github.com/tailwindlabs/tailwindcss-forms and src/index.js contains a verbatim copy of that legitimate plugin. Appended after module.exports = forms; is eval(atob('<large base64 blob>')), which decodes and executes on any require('tailwind-custom-forms'). The decoded payload reconstructs the module names http, https, zlib, url, and child_process from \u escapes to hide its imports, uses child_process.spawn, and builds outbound HTTP requests with keep-alive agents to hosts resolved at runtime from Ethereum JSON-RPC endpoints (eth.blockscout.com/api, 1rpc.io/eth, eth.drpc.org, ethereum-rpc.publicnode.com, eth-mainnet.public.blastapi.io) keyed off the hardcoded ETH address 0xa322E5f3D311D3080e6f0121063e9aDC2490Ef1a, calling paths /0x/cls and /0x/ls. On-chain records act as a rotating dispatcher so the operator can update C2 hosts without republishing the package. Requiring this module executes attacker-controlled code on the installer's machine.
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
Backdoor / remote accessFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for tailwind-custom-forms (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging tailwind-custom-forms across your stack and pipelines.
If you installed it — respond
tailwind-custom-forms establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If tailwind-custom-forms 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 tailwind-custom-forms 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 tailwind-custom-forms-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.