# MAL-2026-5491: Malicious code in xnder-sdk (npm)


- **Type:** Malicious package
- **Package:** `xnder-sdk` (npm)
- **Published:** 10 Jun 2026
- **Also known as:** GHSA-5vr8-6v9x-3vxm

## What is MAL-2026-5491?

MAL-2026-5491 is a malicious package in xnder-sdk, published on 10 Jun 2026. 

### Official description

The package ships scripts/script.js containing heavy obfuscation patterns (string-array shift rotation, hex-encoded numeric literals, while(!![]) control-flow flattening). Obfuscated code in install-time scripts is uncharacteristic of legitimate SDK distributions, which typically ship readable JavaScript or, at most, minified bundles. The obfuscation prevents straightforward verification of what the script does on installer machines. Without de-obfuscating the script and confirming whether it performs network I/O, credential reads, or code execution at install or require time, the specific installer-side behavior cannot be characterized.

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-2026-5491?

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-2026-5491 is a malicious package: xnder-sdk (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-2026-5491/ (Markdown: https://insights.sbomify.com/MAL-2026-5491/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5491

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5491/
Summaries are generated and may contain mistakes; the official description above is the record.