polyfill-corejs3 (npm) · Malicious Code
Affects polyfill-corejs3Source GCVE Database
Malicious package : remove polyfill-corejs3 and rotate any secrets on hosts that installed it.
Data as of 29 Oct 2026, 23:03 UTC
Malicious package
Published to npm · OSV MAL-2025-48777
What to do
Remove polyfill-corejs3 from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| npmpolyfill-corejs3 | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
The polyfill-corejs3 npm package version 9.9.0 contains malicious code that installs a dependency from a custom domain which executes an information stealer during installation. This malware targets sensitive tokens related to npm, git, and CI/CD environments. Systems with this package installed should be considered fully compromised, and all secrets and keys stored on those systems must be rotated immediately from a separate, secure machine.