# MAL-2026-18249: Malicious code in noelc-css-blender (npm)


- **Type:** Malicious package
- **Package:** `noelc-css-blender` (npm)
- **Published:** 24 Oct 2026
- **Also known as:** GHSA-cj2x-975v-jmwf

## What is MAL-2026-18249?

MAL-2026-18249 is a malicious package in noelc-css-blender, published on 24 Oct 2026. 

### Official description

noelc-css-blender@2.1.11 declares itself as a 'tiny ESM utility for blending CSS custom-property token maps' with zero dependencies, but ships two heavily obfuscated single-line files totaling roughly 460 KB: index.mjs (~291 KB) and build-cache.mjs (~177 KB). Both consist of hex-named identifiers (`_0x...`) referencing large custom-encoded string arrays rather than readable code; the declared merge-two-token-maps functionality would require on the order of a dozen lines of plain JavaScript. The files carry fabricated 'auto-generated' header comments that misstate the package identity: index.mjs claims to be auto-generated by noelc-css-blender@2.2.1 (a different version than the actual 2.1.11 package), and build-cache.mjs claims to be auto-generated by tailwindcss-theme-kit@0.2.0, an unrelated package name. The headers additionally include 'restore from package-lock if corrupted' phrasing that functions as cover text discouraging inspection. package.json sets `main: index.mjs`, so any consumer that `require`s or `import`s noelc-css-blender executes the full obfuscated bundle at module load; there are no install lifecycle hooks, so the auto-executed surface is import-time rather than install-time. The string arrays use a custom (non-standard base64/XOR) encoding, so the specific sinks (network destinations, filesystem reads, child_process invocations) could not be extracted verbatim. The combination — massive obfuscated payload, trivial declared purpose, fabricated build-artifact header naming a different package, and import-time auto-execution via `main` — matches the carrier shape of credential-stealer / backdoor payloads rather than a legitimate CSS helper.

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-2026-18249?

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-2026-18249 is a malicious package: noelc-css-blender (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-2026-18249/ (Markdown: https://insights.sbomify.com/MAL-2026-18249/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-18249

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-18249/
Summaries are generated and may contain mistakes; the official description above is the record.