Which versions of css-gvqmfn-polyfill are malicious?

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

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

css-gvqmfn-polyfill establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

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

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

Yes — css-gvqmfn-polyfill is associated with the IN-MAL-2026-021019 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-gvqmfn-polyfill across my projects, lockfiles, and CI pipelines?

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

Malicious package

css-gvqmfn-polyfillnpm

Advisory published Oct 5, 2026Updated Oct 5, 2026

css-gvqmfn-polyfill is a confirmed malicious npm package (MAL-2026-17551) that opens a backdoor for remote access (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in css-gvqmfn-polyfill (npm)

MAL-2026-17551

Immediate action

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

npm uninstall css-gvqmfn-polyfill

What this malware does

css-gvqmfn-polyfill mimics Wix internal @wix/thunderbolt-* CSS polyfill naming and ships a Proxy-based cover stub that re-exports registry names (thunderboltRegistry, siteAssetsRegistry, editorRegistry, corvidRegistry, etc.) as no-op functions to appear functional. On require of thunderboltRegistry.js, an IIFE unconditionally executes id, whoami, uname -a, ifconfig/ip addr, and cat /etc/hosts via child_process, collects os.hostname, Node version, platform, and pid, and sends the output together with an rce-poc beacon to the hardcoded attacker endpoint http://dxpoc.gt.tc/callback.php/bb8968d0f67000433bf7005dd5ad2d1f over plain HTTP. The accompanying registry-manifest.min.json points sibling registries to parastorage.com URLs that do not host this file, consistent with a dependency-confusion lure targeting Wix build environments.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

ffb3f332a818748252e49dcf21ffb6949c531afd401ee697cc08ba00a067ae30

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for css-gvqmfn-polyfill (version 1.0.0).
If you installed it — respond
css-gvqmfn-polyfill establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If css-gvqmfn-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-gvqmfn-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-2026-021019

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks css-gvqmfn-polyfill-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

Explore

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