# MAL-2026-10687: Malicious code in selparsecss-selector (npm)


- **Type:** Malicious package
- **Package:** `selparsecss-selector` (npm)
- **Published:** 15 Jul 2026

## What is MAL-2026-10687?

MAL-2026-10687 is a malicious package in selparsecss-selector, published on 15 Jul 2026. 

### Official description

selparsecss-selector@2.1.0 is a name-confusion fork of postcss-selector-parser: package.json declares author 'Ai Pyramid' <pyramid.info@gmail.com> while the LICENSE-MIT, source tree, API, and CHANGELOG are copied verbatim from the upstream postcss-selector-parser (Ben Briggs). The tarball ships dist/util/webpack.min.js, a ~40KB obfuscator.io-packed bundle with a rotated 757-entry string array and an RC4+base64+XOR string decoder, whose top-level IIFE destructures exec and execSync from child_process, branches on values returned by the os module, and calls process.exit(1) on specific conditions. A CSS-selector parser has no functional need for child_process shell execution. Additionally, propPaths.js and selectors/wrapper.js reconstruct filenames such as 'wrapper.js' and the extension '.jsc' from CSS-hex-escape sequences via an unesc helper, and the package declares bytenode as a runtime dependency; bytenode registers a require hook for opaque V8-bytecode.jsc files, providing a loader path for code that cannot be inspected as source. The combination — impersonated identity, obfuscated child_process-execution bundle, and hex-obfuscated bytenode load scaffolding — is a supply-chain attack shape targeting developers who intended to install postcss-selector-parser.

## What should I do about MAL-2026-10687?

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-2026-10687 is a malicious package: selparsecss-selector (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-2026-10687/ (Markdown: https://insights.sbomify.com/MAL-2026-10687/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-10687

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-10687/
Summaries are generated and may contain mistakes; the official description above is the record.