MAL-2026-6359 Malicious code in html-to-gutenberg (npm)

Malicious package Published
Package
html-to-gutenberg
Registry
npm

What is MAL-2026-6359?

MAL-2026-6359 is a malicious package in html-to-gutenberg, published on 24 Jun 2026.

Official description

The published tarball contains api.js at the package root, a heavily obfuscated loader using an obfuscator.io-style XOR-decoded string table (key 0x46) that reconstructs identifiers including 'constructor', stashes require and module on the global object, and uses Function(…) to compile and immediately invoke an approximately 9.6 KB decoded payload. The file is referenced only by the author's manual scripts.build step (node api.js && tsc); it is not referenced by the package's main entry (index.js), not imported by any reachable module, and not invoked by the declared postinstall. The postinstall script performs a local file-copy of vendor/fetch-page-assets/index.ts into node_modules via fs.copyFileSync with no network I/O and no shell exec of api.js. Because the obfuscated loader is dormant on both npm install and require of the package, no installer-harm dataflow is produced in normal consumer use, but shipping an obfuscated dynamic-eval loader with concealed payload contents in a published tarball is an unusual transparency and supply-chain hygiene concern.

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-2026-6359?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

Sources

Also known as GHSA-2gqj-wrf5-35w8.

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