MAL-2026-17575 Malicious code in css-kfvwax-polyfill (npm)
Malicious package
Published
MAL-2026-17575 is a malicious package: css-kfvwax-polyfill (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-2026-17575/ (Markdown: https://insights.sbomify.com/MAL-2026-17575/index.md)
- Package
- css-kfvwax-polyfill
- Registry
- npm
What is MAL-2026-17575?
MAL-2026-17575 is a malicious package in css-kfvwax-polyfill, published on 5 Oct 2026.
Official description
On require(), thunderboltRegistry.js runs an IIFE that shells out via child_process to collect host identity (
id, whoami, uname -a), network interface listings (ifconfig/ip addr), and the contents of /etc/hosts, together with the machine hostname and a beacon containing Node version, platform, and pid. The collected output is sent via fetch to the hardcoded URL https://unl9pgk6ei4uf80n5tf4iktspjvbuzkn9.oastify.com/ (Burp Collaborator OAST). The module also exports a Proxy mimicking Wix thunderbolt registry APIs (ensureComponentLoadersAreCreated, loadComponents, etc.) under namespaces such as thunderboltRegistry, siteAssetsRegistry, documentManagementRegistry, and editorRegistry, acting as a cover-story API shape consistent with a dependency-confusion or typosquat payload against Wix internal tooling. Installing or importing this package causes host reconnaissance data to be exfiltrated to attacker-controlled infrastructure.What should I do about MAL-2026-17575?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.