# MAL-2026-5896: Malicious code in jest-test-plugin-utils (npm)


- **Type:** Malicious package
- **Package:** `jest-test-plugin-utils` (npm)
- **Published:** 16 Jun 2026
- **Also known as:** GHSA-7969-jc8h-fp32

## What is MAL-2026-5896?

MAL-2026-5896 is a malicious package in jest-test-plugin-utils, published on 16 Jun 2026. 

### Official description

The package advertises itself as a Jest plugin (name: 'jest-test-plugin-utils', description: 'mqtt utils') but ships no Jest or MQTT functionality. Its main entry dist/index.js is a heavily obfuscated 200KB browserify bundle (obfuscator.io fingerprint: 1299-entry rotated string array, decoder wrapper, control-flow flattening; built with the declared devDependency 'gulp-javascript-obfuscator'). After deobfuscation, the only meaningful behavior is a function loadFilbetScriptSilently() (exposed as window.__fetchFilbetScript__) that creates a <script> element with src='https://cdn.jsdelivr.net/gh/gongben2024/network-security@main/src/filbet.js' and appends it to document.head, executing whatever code the author hosts at that mutable @main branch. The destination repository is named 'network-security' under author 'gongben2024' and is unrelated to the package's stated purpose. Because the reference is to the @main branch (not a pinned commit/tag), the author can change the executed payload at any time without republishing this package. Any application that bundles or imports this module will execute attacker-controlled JavaScript in the browser context, with full access to the host page's DOM, cookies, and storage. The combination of name camouflage, heavy obfuscation, and unpinned remote-script execution is a deliberate supply-chain attack pattern.

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-2026-5896?

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-2026-5896 is a malicious package: jest-test-plugin-utils (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-2026-5896/ (Markdown: https://insights.sbomify.com/MAL-2026-5896/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5896

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5896/
Summaries are generated and may contain mistakes; the official description above is the record.