# MAL-2026-17488: Malicious code in css-starting-style-polyfill (npm)


- **Type:** Malicious package
- **Package:** `css-starting-style-polyfill` (npm)
- **Published:** 4 Oct 2026

## What is MAL-2026-17488?

MAL-2026-17488 is a malicious package in css-starting-style-polyfill, published on 4 Oct 2026. 

### Official description

thunderboltRegistry.js runs an IIFE on module load that executes host reconnaissance commands via child_process.execSync (id, whoami, uname -a, ifconfig/ip addr, cat /etc/hosts) and transmits the collected output together with hostname, platform, and pid to a hardcoded external URL https://dxpoc.gt.tc/callback.php/bb8968d0f67000433bf7005dd5ad2d1f via fetch. The package exports factories under names matching Wix internal registry modules (thunderboltRegistry, corvidRegistry, siteAssetsRegistry, editorRegistry, documentManagementRegistry) and ships a manifest referencing parastorage.com URLs, so any environment loading it as a drop-in Wix thunderbolt registry triggers the exfiltration payload on require(). The declared CSS @starting-style polyfill purpose has no relationship to the shipped behavior.

## What should I do about MAL-2026-17488?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-17488 is a malicious package: css-starting-style-polyfill (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-17488/ (Markdown: https://insights.sbomify.com/MAL-2026-17488/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-17488

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-17488/
Summaries are generated and may contain mistakes; the official description above is the record.