# MAL-2026-6453: Malicious code in simple-node-calc-b (npm)


- **Type:** Malicious package
- **Package:** `simple-node-calc-b` (npm)
- **Published:** 25 Jun 2026

## What is MAL-2026-6453?

MAL-2026-6453 is a malicious package in simple-node-calc-b, published on 25 Jun 2026. 

### Official description

simple-node-calc-b@1.0.0 ships a binding.gyp that includes a `modules` file declaring `"lodash": "<!(node lodash-compiler.js)"`. The gyp `<!(...)` syntax executes shell commands at parse time, and npm auto-invokes node-gyp on any package containing binding.gyp during `npm install`, so `node lodash-compiler.js` runs automatically on every install with no user opt-in. lodash-compiler.js is an 87KB obfuscator.io-style packed script (524-entry rotated string array `_0x2f6e`, decoder wrapper, control-flow flattening switch/case dispatcher, hex variable names) reachable through this auto-execution path. The script body contains `require('fs').writeFileSync(...)` along with string-array fragments `'poc.txt'`, `'Security P'`, `'OC.'`, `'writeFileS'`, `'ync'` — self-describing as a proof-of-concept payload. The package name advertises a calculator; there is no legitimate reason for a calculator to ship 87KB of obfuscated code behind a hidden gyp shell-expansion. The combination of auto-execution on default install, heavy obfuscation, purpose mismatch, and self-described POC payload matches the canonical install-time RCE pattern.

## What should I do about MAL-2026-6453?

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-2026-6453 is a malicious package: simple-node-calc-b (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-2026-6453/ (Markdown: https://insights.sbomify.com/MAL-2026-6453/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6453

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-6453/
Summaries are generated and may contain mistakes; the official description above is the record.