vite-config-optimizernpm
vite-config-optimizer is a confirmed malicious npm package (MAL-2026-5727) that executes malicious code on install (malicious version 1.1.4). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in vite-config-optimizer (npm)
What this malware does
package.json declares a postinstall hook node -e "require('./loader.js')" that auto-executes on every npm install. loader.js spawns a detached child Node process running a dropper that hex-decodes a hidden URL (https://jsonkeeper.com/b/L435A, an anonymous, mutable JSON paste host), HTTPS-GETs the response body, writes it to a temp file under /tmp/wpc-*/cfg-*.js, and require()s it — running arbitrary attacker-controlled JavaScript inside the installer's Node process with the installer's privileges. The remote endpoint is concealed as a hex literal decoded with Buffer.from(..., 'hex').toString() to evade plain-text URL scanners, and the dropper is detached and unref'd to hide its activity. The package's advertised identity is also a cover story: the name and description claim it is a Vite configuration plugin, but the declared repository points at webpack-tools/webpack-cache-plugin, the main module exports a WebpackCachePlugin class, and the only install-time behavior is the dropper. Anyone running npm install vite-config-optimizer (directly or transitively) executes whatever bytes the paste host serves at request time.
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
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for vite-config-optimizer (version 1.1.4). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging vite-config-optimizer across your stack and pipelines.
If you installed it — respond
Remove vite-config-optimizer 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 vite-config-optimizer 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 vite-config-optimizer 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 vite-config-optimizer-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.