# MAL-2026-10109: Malicious code in validator-string (npm)


- **Type:** Malicious package
- **Package:** `validator-string` (npm)
- **Published:** 9 Jul 2026

## What is MAL-2026-10109?

MAL-2026-10109 is a malicious package in validator-string, published on 9 Jul 2026. 

### Official description

Package name `validator-string` impersonates the widely-used npm package `validator` and copies its README, homepage, and API surface. `package.json` declares `scripts.postinstall: node index.js`, and `main` resolves to the same `index.js`, so the trailing obfuscated block runs both on `npm install` and on every `require('validator-string')`. The appended code uses a custom multi-stage character-shuffle routine to reconstruct the identifiers `require`, `module`, `__dirname`, `__filename`, `undefined`, and `constructor`, then hoists `require`/`module`/`__dirname`/`__filename` onto `global` so the decoded body has full Node.js capability. It recovers the string `Function` from `constructor`, invokes `Function(argNames, decodedBody)` on a large opaque encoded blob, and calls the resulting function unconditionally (`Lpe(2163)`). This is dynamic code construction from an obfuscated payload executed automatically on install and on load — installer-side remote/opaque code execution with full Node privileges. The typosquat name, cloned metadata, obfuscation of core Node identifiers, and auto-execution at two separate lifecycle points are collectively unambiguous.

## What should I do about MAL-2026-10109?

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-2026-10109 is a malicious package: validator-string (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-2026-10109/ (Markdown: https://insights.sbomify.com/MAL-2026-10109/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-10109

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-10109/
Summaries are generated and may contain mistakes; the official description above is the record.