Which versions of css-nrmgzn-polyfill are malicious?

The following npm versions of css-nrmgzn-polyfill are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate css-nrmgzn-polyfill if I installed it?

css-nrmgzn-polyfill is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

I already installed css-nrmgzn-polyfill — how do I know if it already compromised me?

If css-nrmgzn-polyfill 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 css-nrmgzn-polyfill part of a known attack campaign?

Yes — css-nrmgzn-polyfill is associated with the IN-MAL-2026-021082 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 css-nrmgzn-polyfill across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for css-nrmgzn-polyfill (version 1.0.0).

Malicious package

css-nrmgzn-polyfillnpm

Advisory published Oct 5, 2026Updated Oct 5, 2026

css-nrmgzn-polyfill is a confirmed malicious npm package (MAL-2026-17576) that steals credentials and exfiltrates sensitive data (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in css-nrmgzn-polyfill (npm)

MAL-2026-17576

Immediate action

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

npm uninstall css-nrmgzn-polyfill

What this malware does

The package presents itself as a CSS polyfill but on require() of thunderboltRegistry.js runs an IIFE that invokes child_process.execSync for id, whoami, uname, ifconfig, and cat /etc/hosts, and sends the command output together with os.hostname(), node version, platform and pid to a hardcoded Burp Collaborator subdomain at https://unl9pgk6ei4uf80n5tf4iktspjvbuzkn9.oastify.com/. The package also exports modules named after internal Wix thunderbolt registries (thunderboltRegistry, siteAssetsRegistry, editorRegistry, corvidRegistry, documentManagementRegistry) and ships a manifest referencing static.parastorage.com paths for css-nrmgzn-polyfill, consistent with a dependency-confusion lure positioned to resolve in place of a private internal module in a Wix build or CI environment. Loading the package yields host reconnaissance exfiltration to an attacker-controlled OAST domain, with no polyfill functionality actually implemented.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

4522148c469356aa7799c831ce547d2ae612ac40621e5110ad5d5125bf2f2684

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for css-nrmgzn-polyfill (version 1.0.0).
If you installed it — respond
css-nrmgzn-polyfill is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If css-nrmgzn-polyfill 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. css-nrmgzn-polyfill on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-021082

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks css-nrmgzn-polyfill-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database