# MAL-2026-12418: Malicious code in postcss-animate-css-vars (npm)


- **Type:** Malicious package
- **Package:** `postcss-animate-css-vars` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-432g-6qr7-8hvh

## What is MAL-2026-12418?

MAL-2026-12418 is a malicious package in postcss-animate-css-vars, published on 5 Aug 2026. 

### Official description

src/normalize-options.js is heavily obfuscated (RC4-decoded string array, hex-numeric literals, rotating string-array shuffler, dead-code comparison branches) while the rest of the package (index.js, plugin.js, root.js, declarations.js) is plain readable code. When the PostCSS plugin is instantiated (createPlugin -> normalizeOptions), the loader assembles an HTTPS URL from obfuscated string-array entries, appends keys from the caller-supplied options.features sub-object as query parameters, fetches a JSON response, base64-decodes its `message` field, and executes the decoded code with `new Function('require', code)(require)` — arbitrary code execution in every downstream consumer's build/CI process. The loader also writes a wrapper file to the OS tmpdir (named with process.pid) containing `require('<pkg>')(<options>); setInterval(()=>{},2147483647);` and spawns `process.execPath` detached with stdio ignored and env `LT1_STAGE1_CHILD=1`, then calls `child.unref()`. The detached node child re-enters the loader branch, decoupling the fetch-and-eval from the parent build and keeping it alive on a ~24.8-day interval after PostCSS exits, enabling persistent staging beyond the build window. Package metadata (name postcss-animate-css-vars, description 'PostCSS plugin for animate.css', author 'Alex Rivera <alex@cssanimation.dev>', homepage cssanimation.dev) presents as a legitimate PostCSS ecosystem plugin, but the shipped code contains no animate.css handling in the obfuscated loader path — the metadata is cover for the loader.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-12418?

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-2026-12418 is a malicious package: postcss-animate-css-vars (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-2026-12418/ (Markdown: https://insights.sbomify.com/MAL-2026-12418/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12418

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12418/
Summaries are generated and may contain mistakes; the official description above is the record.