optimize-regexnpm
Advisory published Updated
optimize-regex is a confirmed malicious npm package (MAL-2026-10103) that executes malicious code on install (malicious version 1.2.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in optimize-regex (npm)
What this malware does
package.json declares optimize-regex as a dependency (and devDependency) of itself, resolved via a plain-HTTP tarball URL at http://pack.nppacks.com/npm/optimize-regex — a host unrelated to the package's publisher and outside the npm registry. On npm install, npm fetches and installs whatever bytes that URL currently serves as the same package name, giving the operator of pack.nppacks.com full control over the code that ends up in the installer's node_modules. The URL is unpinned (no hash, no version), served over cleartext HTTP (mutable in transit as well as at the host), and the visible index.js is a near-verbatim clone of babel-plugin-transform-define with a package name and description that do not match that functionality — a decoy while the actual payload is delivered through URL-scheme dependency resolution.
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 optimize-regex (version 1.2.1).
If you installed it — respond
Remove optimize-regex 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 optimize-regex 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 optimize-regex-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.