# MAL-2026-12621: Malicious code in claims-get-indexed-selector (npm)


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

## What is MAL-2026-12621?

MAL-2026-12621 is a malicious package in claims-get-indexed-selector, published on 5 Aug 2026. 

### Official description

claims-get-indexed-selector@35.8.7 executes a binary dropper on module load. index.js unconditionally requires _polyfill.js, which reassembles network destinations from split string arrays (hosts on cf*.workers.dev and *.dl.wel1.ru), downloads a native binary over HTTPS, writes it to /var/tmp/.cache_<hex> or TEMP\dotnet_diag_<hex>.exe with cover-story filenames, chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start /b. If HTTPS retrieval fails, a covert DNS-TXT channel is used: a chunk-count TXT record at c.<domain> and base64-encoded payload chunks at <i>.<domain> are fetched and reassembled into the executable. No hash or signature verification is performed on the fetched binary. Destination hostnames are constructed from split arrays such as ["oob-worker",".cf103-070.","workers.","de","v"].join("") to evade static string scanning. The package is presented as a benign runtime support module; the delivered binary is opaque and the destinations are attacker-controlled.

## What should I do about MAL-2026-12621?

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-2026-12621 is a malicious package: claims-get-indexed-selector (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-2026-12621/ (Markdown: https://insights.sbomify.com/MAL-2026-12621/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12621

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12621/
Summaries are generated and may contain mistakes; the official description above is the record.