# MAL-2026-12611: Malicious code in claims-constants (npm)


- **Type:** Malicious package
- **Package:** `claims-constants` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-12611?

MAL-2026-12611 is a malicious package in claims-constants, published on 5 Aug 2026. 

### Official description

The package's index.js unconditionally requires./_helpers.js, whose top-level main() executes on import. It downloads a platform-specific binary from obfuscated Cloudflare Workers subdomains (oob-worker.cf103-070.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS-TXT covert-channel fallback under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The fetched bytes are written to /var/tmp or %TEMP% under disguised names (dotnet_diag_*.exe,.cache_*), chmodded to 0755, and spawned detached via cp.spawn("/bin/sh", ["-c", fp + " &"], {detached:true}).unref(). Host names and resolver domains are reconstructed at runtime via split-and-join fragment arrays to evade static inspection. The DNS-TXT fallback fetches a chunk count from c.<domain>, iterates N.<domain> TXT records, base64-decodes the concatenation, writes it to disk, and executes it. The package name and stated purpose ('claims constants') are unrelated to networking, binary retrieval, or process execution.

## What should I do about MAL-2026-12611?

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-2026-12611 is a malicious package: claims-constants (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-2026-12611/ (Markdown: https://insights.sbomify.com/MAL-2026-12611/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12611

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12611/
Summaries are generated and may contain mistakes; the official description above is the record.