# MAL-2026-5492: Malicious code in xnder-wrapper-module (npm)


- **Type:** Malicious package
- **Package:** `xnder-wrapper-module` (npm)
- **Published:** 10 Jun 2026
- **Also known as:** GHSA-jxcv-3994-r8xf

## What is MAL-2026-5492?

MAL-2026-5492 is a malicious package in xnder-wrapper-module, published on 10 Jun 2026. 

### Official description

package.json declares `"postinstall": "node scripts/script.js"`, causing scripts/script.js to run automatically on every `npm install`. That file is the package's only functional code and is heavily obfuscated (obfuscator.io string-array with a 242-entry rotated table, RC4 decoder `String.fromCharCode(l.charCodeAt(t) ^ n[(n[r]+n[o])%256])`, control-flow flattening, webpack-bundled across 5 modules requiring path/os/fs/child_process and an HTTP client). The decoded flow constructs a URL via string concatenation tricks (`repeat('.')`, `concat('.')`), performs an HTTPS GET, writes the response body to a file under `os.tmpdir()` via `fs.writeFileSync(..., {flag:'w+'})`, and then runs `execSync(..., {windowsHide:true, cwd: os.tmpdir()})` against the dropped file — the standard fetch/drop/execute dropper shape with a sandbox-evasion flag. The package ships no other functionality; the README explicitly tells users the payload is unreviewed and recommends running it only inside a VM/Docker. Installing this package on a default `npm install` runs attacker-controlled code on the developer's machine.

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-2026-5492?

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-2026-5492 is a malicious package: xnder-wrapper-module (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-2026-5492/ (Markdown: https://insights.sbomify.com/MAL-2026-5492/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5492

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-5492/
Summaries are generated and may contain mistakes; the official description above is the record.