# MAL-2026-5638: Malicious code in tw-fluid-type (npm)


- **Type:** Malicious package
- **Package:** `tw-fluid-type` (npm)
- **Published:** 11 Jun 2026
- **Also known as:** GHSA-53h7-3qgm-jr76

## What is MAL-2026-5638?

MAL-2026-5638 is a malicious package in tw-fluid-type, published on 11 Jun 2026. 

### Official description

The package advertises itself as a Tailwind CSS fluid-type plugin but ships src/utils/lib.min.js, which is loaded as a side effect when the package's main entry point is required. createClasses.js (reached from src/index.js) does `const lib = require('./lib.min.js')` and never uses the returned value — the only purpose of the require is to trigger the file's IIFE. lib.min.js caches `global.r = require` and `global.m = module`, then runs a ~4KB string through a custom Fisher-Yates-style deterministic shuffle (function YWG, seed 2540575) to decode JavaScript source, resolves the Function constructor via an obfuscated property lookup (`YWG['constructor']`), and invokes `Function(...)(decoded_body)` to execute the decoded code with full access to the cached require/module. A declarative CSS-utility plugin has no legitimate need to construct functions from shuffled-string blobs, cache require/module on the global object, or conceal its executable logic with a custom shuffle. Any consumer who imports this package executes the concealed payload at module load.

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-2026-5638?

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-2026-5638 is a malicious package: tw-fluid-type (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-2026-5638/ (Markdown: https://insights.sbomify.com/MAL-2026-5638/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5638

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5638/
Summaries are generated and may contain mistakes; the official description above is the record.