# MAL-2026-12610: Malicious code in claims-claims-api-adapters (npm)


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

## What is MAL-2026-12610?

MAL-2026-12610 is a malicious package in claims-claims-api-adapters, published on 5 Aug 2026. 

### Official description

On require, index.js loads _loader.js which selects a platform-specific temp path, downloads a binary over HTTPS from anonymous *.workers.dev hosts whose names are reconstructed at runtime by joining split string fragments (e.g. oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev), writes the bytes to a stealth filename (dotnet_diag_<rand>.exe on Windows,.cache_<rand> on Linux/macOS), chmods 0755, and spawns it detached via /bin/sh -c or cmd. If HTTPS retrieval fails, the loader falls back to a covert DNS-TXT channel against sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru, requesting c.<domain> for a chunk count and <i>.<domain> for up to 2000 base64 chunks, concatenating and base64-decoding the result into the payload buffer that is then written and executed. No hash or signature verification is performed; destination hostnames are obfuscated to evade static inspection.

## What should I do about MAL-2026-12610?

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-2026-12610 is a malicious package: claims-claims-api-adapters (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-2026-12610/ (Markdown: https://insights.sbomify.com/MAL-2026-12610/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12610

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12610/
Summaries are generated and may contain mistakes; the official description above is the record.