# MAL-2026-12169: Malicious code in bigops-header-tabs (npm)


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

## What is MAL-2026-12169?

MAL-2026-12169 is a malicious package in bigops-header-tabs, published on 5 Aug 2026. 

### Official description

On require() of bigops-header-tabs, index.js loads _adapter.js which selects a platform-specific remote path and fetches an opaque binary from obfuscated Cloudflare Workers hosts (hostnames reconstructed by string-join, e.g. "oob-worker.cf10"+"2-baf.workers.dev"), with a DNS-TXT-record-based staged retrieval fallback via subdomains of dl.wel1.ru (c.<domain> for chunk count, i.<domain> for base64 chunks). The fetched payload is written to /tmp or %TEMP% under masquerading names (dotnet_diag_,.cache_, analytics_state), chmod 0755 on Unix, and spawned detached via /bin/sh -c or cmd.exe. Execution is gated by env-var opt-outs and a stamp file to run once per host. The package README advertises only a trivial "header tabs" SDK, which does not require any native binary or child-process execution. Fingerprints present: hardcoded/reconstructed attacker C2 bound to install-time-reachable network+exec, obfuscated destination hostnames, DNS covert channel, filename masquerade, purpose mismatch between advertised functionality and shipped behavior.

## What should I do about MAL-2026-12169?

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-2026-12169 is a malicious package: bigops-header-tabs (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-2026-12169/ (Markdown: https://insights.sbomify.com/MAL-2026-12169/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12169

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12169/
Summaries are generated and may contain mistakes; the official description above is the record.