polyfill-corejs2npm
Malicious code in polyfill-corejs2 (npm) Remove it immediately and rotate any exposed credentials.
What this malware does
The package polyfill-corejs2 was found to contain malicious code.
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 polyfill-corejs2 (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging polyfill-corejs2 across your stack and pipelines.
If you installed it — respond
Remove polyfill-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 polyfill-corejs2 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 polyfill-corejs2 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
Credits
- Amazon Inspector · finder
- ReversingLabs · finder
Detect & block this
O3 blocks polyfill-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.