css-scroll-state-polyfill

Details

**Severity:** Critical

**Affected versions:** `= 1.0.0`

## Source: amazon-inspector (cffa0affc34bac3fa24fcc7c67aae4d120066f4f856cb8b637bc04c6ca9d482c)
The package presents itself as a CSS polyfill but ships a payload file (thunderboltRegistry.js) that executes an IIFE at require time. The IIFE uses child_process to run host-identification commands (id, whoami, uname -a, ifconfig/ip addr, /etc/hosts, hostname) and collects Node version, platform, and PID, then sends the captured data via fetch to a hardcoded webhook.site collector at https://webhook.site/0492a36c-4d7b-408a-865c-226db25987ba. The main index.js is an empty stub; filenames mimic internal Wix Thunderbolt registry modules, consistent with a dependency-confusion squat targeting that namespace. A self-identifying 'beacon=poc15' tag is included in the request. The payload also walks require.cache and deletes any entry whose key contains 'thunderboltRegistry', causing subsequent requires in the same process to re-execute the recon-and-exfiltration path rather than return a cached export, and exports a Proxy that answers arbitrary method accesses to blend in with the impersonated registry.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/7a1f1382a84618fabc1c45e8b61e9c9cea6ea33f/osv/malicious/npm/css-scroll-state-polyfill/MAL-2026-17486.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/7a1f1382a84618fabc1c45e8b61e9c9cea6ea33f/osv/malicious/npm/css-scroll-state-polyfill/MAL-2026-17486.json
- https://www.npmjs.com/package/css-scroll-state-polyfill/v/1.0.0
- https://github.com/advisories/GHSA-wwwp-g75q-ww7r

Compromised versions (1)

• = 1.0.0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.