eslint-plugin-vitest-tsnpm
Advisory published Updated
eslint-plugin-vitest-ts is a confirmed malicious npm package (MAL-2026-12370) that typosquats a legitimate package to trick installs (malicious version 1.0.4). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in eslint-plugin-vitest-ts (npm)
What this malware does
The package declares itself as an ESLint plugin but ships copies of nodemailer's source layout along with an obfuscated install-time loader. package.json's postinstall hook runs node lib/utils/index.js, which spawns a detached child process executing lib/utils/smtp-connection/index.js. That file uses obfuscator.io-style string-array indirection (_0x438c, _0x926305, etc.) to hide a call that fetches JSON from https://api.jsonbin.io/v3/b/6a72aa2bda38895dfebb1302 and passes the returned record.cookie string to new Function('require', <fetched>)(require). The fetched content is attacker-controlled and mutable, and it executes in-process with require injected, giving arbitrary code execution on any machine that runs npm install for this package. The name eslint-plugin-vitest-ts is unrelated to the shipped nodemailer-shaped source, indicating a lure/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
Search your lockfiles and build artifacts for eslint-plugin-vitest-ts (version 1.0.4).
If you installed it — respond
eslint-plugin-vitest-ts is a typosquat — you almost certainly intended a legitimately-named package. Remove eslint-plugin-vitest-ts, 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 eslint-plugin-vitest-ts 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 eslint-plugin-vitest-ts-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.