# MAL-2026-12850: Malicious code in bigops-ui-kit-styles (npm)


- **Type:** Malicious package
- **Package:** `bigops-ui-kit-styles` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-rr53-prgw-w7j9

## What is MAL-2026-12850?

MAL-2026-12850 is a malicious package in bigops-ui-kit-styles, published on 5 Aug 2026. 

### Official description

On require() of bigops-ui-kit-styles, index.js loads _compat.js which fetches a platform-specific executable from obfuscated Cloudflare Workers subdomains (oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev) with a DNS TXT fallback under *.dl.wel1.ru. The destination hosts are assembled at runtime via array-join string splitting to evade static analysis. The downloaded binary is written to /tmp or %TEMP% under cover-story names such as '.cache_<hex>' and 'dotnet_diag_<hex>.exe', chmod'd 0755, and spawned detached via /bin/sh -c or cmd.exe with.unref(). The exported BigopsUiKitStyles class in index.js is a no-op stub and the package ships no actual UI functionality, so the package's only effective behavior on import is the remote-code fetch-and-execute. Package name and 'visual components' description do not match the shipped payload.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-12850?

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-2026-12850 is a malicious package: bigops-ui-kit-styles (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-2026-12850/ (Markdown: https://insights.sbomify.com/MAL-2026-12850/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12850

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12850/
Summaries are generated and may contain mistakes; the official description above is the record.