MAL-2026-16101 Malicious code in mfaby (npm)
Malicious package
Published
MAL-2026-16101 is a malicious package: mfaby (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-2026-16101/ (Markdown: https://insights.sbomify.com/MAL-2026-16101/index.md)
- Package
- mfaby
- Registry
- npm
What is MAL-2026-16101?
MAL-2026-16101 is a malicious package in mfaby, published on 9 Sep 2026.
Official description
The package presents itself as a Discord MFA helper, but its cache module contains a _warmSession routine that decodes a base64-encoded string (_CDN_BASE) into the URL https://limbomail.com/api/attachment/l4TIRPOsaUxR._603-vhKDRdgKl3RalN_TVUZYGPsJy2Y, downloads the response body, writes it to a file in os.tmpdir(), and executes it via new Worker(tmp). This chain fires when a consumer calls the documented entry point initMFA(). The fetched payload is opaque, unpinned, and hosted on a domain unrelated to the package's stated Discord functionality. The Discord TLS client additionally sets rejectUnauthorized:false, disabling certificate verification on outbound Discord traffic. The base64 concealment of the drop URL combined with a README cover-story describing it as a 'runtime patch asset' indicates deliberate hiding of the endpoint.
What should I do about MAL-2026-16101?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.