Which versions of babel-polyfill-plugin-corejs2 are malicious?

The following npm versions of babel-polyfill-plugin-corejs2 are flagged malicious: 1.0.1. Treat any of these as compromised.

How do I remediate babel-polyfill-plugin-corejs2 if I installed it?

Remove babel-polyfill-plugin-corejs2 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.

I already installed babel-polyfill-plugin-corejs2 — how do I know if it already compromised me?

If babel-polyfill-plugin-corejs2 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.

Is babel-polyfill-plugin-corejs2 part of a known attack campaign?

Yes — babel-polyfill-plugin-corejs2 is associated with the IN-MAL-2026-018647 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find babel-polyfill-plugin-corejs2 across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for babel-polyfill-plugin-corejs2 (version 1.0.1).

Malicious package

babel-polyfill-plugin-corejs2npm

Advisory published Aug 24, 2026Updated Aug 24, 2026

babel-polyfill-plugin-corejs2 is a confirmed malicious npm package (MAL-2026-14426) that executes malicious code on install (malicious version 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in babel-polyfill-plugin-corejs2 (npm)

MAL-2026-14426

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall babel-polyfill-plugin-corejs2

What this malware does

The package advertises itself as a Babel core-js 2 polyfill plugin, but the shipped lib/index.js contains unrelated web3-core-subscriptions boilerplate followed by a Function() invocation whose body is ~110KB of obfuscated JavaScript (random identifiers, numeric offset arrays, TEA-like mixing routine, unicode-escape string literals). The Function() call executes whenever a consumer require()s the package, running the opaque payload at import time. The declared purpose does not match the shipped code, and the obfuscation is confined to the appended payload rather than being a general minification artifact.

Malicious versions

1 flagged

1.0.1

Indicators of compromise (SHA-256)

13878d994b01607c379e26646449b7cca95099f9b2eb5be2e1f8e19aeea32eb3

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for babel-polyfill-plugin-corejs2 (version 1.0.1).
If you installed it — respond
Remove babel-polyfill-plugin-corejs2 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 babel-polyfill-plugin-corejs2 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

No. babel-polyfill-plugin-corejs2 on npm has been identified as a malicious package (version 1.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-018647

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks babel-polyfill-plugin-corejs2-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.

Malware detection Runtime egress monitoring

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