# MAL-2026-12164: Malicious code in bigops-eslint-config (npm)


- **Type:** Malicious package
- **Package:** `bigops-eslint-config` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-12164?

MAL-2026-12164 is a malicious package in bigops-eslint-config, published on 5 Aug 2026. 

### Official description

The package presents itself as an ESLint config but on require() unconditionally loads _vendor.js, which selects a platform-specific asset, fetches a binary via https.get from string-concatenation-obfuscated Cloudflare Workers hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf100-416.workers.dev), with a DNS-TXT chunked-base64 fallback to *.dl.wel1.ru (sdk/ext/pkg/net.dl.wel1.ru). The downloaded bytes are written to /var/tmp or %TEMP% under disguised names (.cache_<hex>, dotnet_diag_<hex>.exe), chmodded 0755, and spawned detached via cp.spawn('/bin/sh', ['-c', fp+' &'], {detached:true}).unref(). Endpoint strings are assembled from array joins to evade static inspection; a sibling lib/telemetry.js uses require('child_' + 'process') and fs['chmod'+'Sync'] to further hide the sinks. The package name and 'environment config reader' description are unrelated to this behavior. No hash/signature verification, no version pinning, and the hosts are anonymous mutable infrastructure — arbitrary attacker code runs on the installer's host on import.

## What should I do about MAL-2026-12164?

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-2026-12164 is a malicious package: bigops-eslint-config (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-2026-12164/ (Markdown: https://insights.sbomify.com/MAL-2026-12164/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12164

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12164/
Summaries are generated and may contain mistakes; the official description above is the record.