🛡️ MAL-2026-5896 — jest-test-plugin-utils

Malicious code in jest-test-plugin-utils (npm)

Source: amazon-inspector

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.

Source: ghsa-malware

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.