# MAL-2026-12639: Malicious code in claims-policy-details-api-adapters (npm)


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

## What is MAL-2026-12639?

MAL-2026-12639 is a malicious package in claims-policy-details-api-adapters, published on 5 Aug 2026. 

### Official description

On require of the package, index.js loads _loader.js which downloads a platform-specific binary from string-split-obfuscated hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-TXT chunked-base64 fallback channel across sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The fetched bytes are written to /tmp or %TEMP% under cover names such as.cache_<hex> or dotnet_diag_<hex>.exe, chmodded to 0755, and spawned detached via spawn("/bin/sh", ["-c", <path> + " &"], {detached:true, stdio:"ignore"}). Hostnames are assembled from split arrays (e.g. ["oob-worker.cf103-070.wo","rke","rs.dev"].join("")) and no hash or signature verification is performed despite comments referencing SHA-256 integrity. The DNS-TXT retrieval path queries c.<domain> for a chunk count and N.<domain> for base64 chunks that are concatenated and decoded to a Buffer, providing a covert channel that bypasses URL/domain egress controls.

## What should I do about MAL-2026-12639?

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-2026-12639 is a malicious package: claims-policy-details-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-2026-12639/ (Markdown: https://insights.sbomify.com/MAL-2026-12639/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12639

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12639/
Summaries are generated and may contain mistakes; the official description above is the record.