# MAL-2026-17550: Malicious code in css-dwsawd-polyfill (npm)


- **Type:** Malicious package
- **Package:** `css-dwsawd-polyfill` (npm)
- **Published:** 5 Oct 2026

## What is MAL-2026-17550?

MAL-2026-17550 is a malicious package in css-dwsawd-polyfill, published on 5 Oct 2026. 

### Official description

The package name mimics a Wix thunderbolt polyfill and ships a registry-manifest.min.json that aliases legitimate @wix thunderbolt registry module names to thunderboltRegistry.js. On require, thunderboltRegistry.js runs an IIFE that uses child_process.execSync to execute shell reconnaissance (id, whoami, uname -a, ifconfig/ip addr, /etc/hosts) and fetches http://dxpoc.gt.tc/callback.php/bb8968d0f67000433bf7005dd5ad2d1f with the command outputs plus hostname, pid, platform, node version, and a site identifier as query parameters, tagged 'rce-poc'. A fallback path constructs a fresh Module instance to re-resolve child_process if the require cache is stubbed, ensuring execution. The destination is plain HTTP to an unrelated external host and is not caller-configurable.

## What should I do about MAL-2026-17550?

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-2026-17550 is a malicious package: css-dwsawd-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-2026-17550/ (Markdown: https://insights.sbomify.com/MAL-2026-17550/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-17550

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-17550/
Summaries are generated and may contain mistakes; the official description above is the record.