# MAL-2026-13248: Malicious code in bigops-rx-post-message (npm)


- **Type:** Malicious package
- **Package:** `bigops-rx-post-message` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-13248?

MAL-2026-13248 is a malicious package in bigops-rx-post-message, published on 5 Aug 2026. 

### Official description

On require() of bigops-rx-post-message, index.js executes _init.js at module top level, which downloads a platform-specific binary from Cloudflare Workers hosts whose names are assembled at runtime from string-split arrays (e.g. oob-worker.cf10x-*.workers.dev) with a DNS-TXT base64 fallback across sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched bytes are written under /var/tmp or %TEMP% with a disguised name (.cache_<hex> / dotnet_diag_<hex>.exe), chmodded 0755, and spawn-detached via /bin/sh -c or cmd.exe. No hash or signature verification is performed, the destinations are not the publisher's infrastructure, and lib/telemetry.js contains the same dropper primitives with `child_process` obtained via string concatenation (require("child_"+"process")) and fs["chmod"+"Sync"] indexed by string to evade static scanners. Installing or requiring this package causes an unpinned, attacker-controlled executable to run on the installer's host.

## What should I do about MAL-2026-13248?

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-2026-13248 is a malicious package: bigops-rx-post-message (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-2026-13248/ (Markdown: https://insights.sbomify.com/MAL-2026-13248/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-13248

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-13248/
Summaries are generated and may contain mistakes; the official description above is the record.