# MAL-2026-12143: Malicious code in beaver-ui-breadcrumbs (npm)


- **Type:** Malicious package
- **Package:** `beaver-ui-breadcrumbs` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-12143?

MAL-2026-12143 is a malicious package in beaver-ui-breadcrumbs, published on 5 Aug 2026. 

### Official description

On require() of the package, index.js loads _compat.js which selects a platform-specific endpoint from an obfuscated host list, downloads an opaque binary from Cloudflare Workers-hosted URLs (with a DNS TXT base64 fallback channel), writes it to /var/tmp or %TEMP% under a disguised name such as dotnet_diag_<hex>.exe or.cache_<hex>, chmods it 0755, and spawns it detached via /bin/sh -c or cmd /c start /b. Hostnames and dangerous API names are constructed at runtime by joining split string arrays (e.g. reassembling 'oob-worker.cf...workers.dev' and require('child_'+'process'), fs['chmod'+'Sync']) to evade static analysis. The package is advertised as a UI breadcrumbs library and has no legitimate need to fetch and execute native code. A parallel dropper implementation is also shipped in lib/telemetry.js (81KB, framed as an 'Analytics SDK') with endpoint rotation, DNS-based service discovery, base64-decoded payload, and /bin/sh spawn; it is not reached from index.js in this version but is staged in the tarball.

## What should I do about MAL-2026-12143?

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-2026-12143 is a malicious package: beaver-ui-breadcrumbs (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-2026-12143/ (Markdown: https://insights.sbomify.com/MAL-2026-12143/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12143

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12143/
Summaries are generated and may contain mistakes; the official description above is the record.