# MAL-2026-6451: Malicious code in simple-node-calc-a (npm)


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

## What is MAL-2026-6451?

MAL-2026-6451 is a malicious package in simple-node-calc-a, published on 25 Jun 2026. 

### Official description

simple-node-calc-a@1.0.0 advertises itself as a pure-JS calculator but ships a binding.gyp that triggers node-gyp automatically during `npm install`. binding.gyp line 6 uses gyp's shell-expansion directive `"<!(node lodash-compiler.js && echo stub.c)"`, which executes the sibling file `lodash-compiler.js` in the installer's environment at configure time, before any user code runs. lodash-compiler.js is an 87 KB obfuscator.io-packed file (rotated 510-entry `_0x` string array, control-flow flattening, 2906 deobfuscation transforms) presented with a lodash custom-build banner but never declared as a dependency and never imported by index.js. The deobfuscated trailer resolves to `require('fs').writeFileSync('poc.txt', 'POC...')`, writing a file into the installer's current working directory outside the package's own folder. The combination — undocumented native-build hook in a package with no native code, heavily obfuscated payload reachable only via that hook, and a write to the installer's CWD — is a working install-time arbitrary-code-execution primitive. Today's payload drops a PoC marker file; the same channel can deliver any code the author chooses on subsequent versions.

## What should I do about MAL-2026-6451?

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-2026-6451 is a malicious package: simple-node-calc-a (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-2026-6451/ (Markdown: https://insights.sbomify.com/MAL-2026-6451/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6451

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-6451/
Summaries are generated and may contain mistakes; the official description above is the record.