# MAL-2026-12554: Malicious code in checkout-desktop-bnpl (npm)


- **Type:** Malicious package
- **Package:** `checkout-desktop-bnpl` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-12554?

MAL-2026-12554 is a malicious package in checkout-desktop-bnpl, published on 5 Aug 2026. 

### Official description

The package presents itself as a checkout/BNPL library but exports an empty CheckoutDesktopBnpl class with no BNPL functionality. On require() of the main module, index.js loads _polyfill.js, which selects a platform-specific remote endpoint, downloads a binary payload, writes it to /tmp or %TEMP% under decoy names such as dotnet_diag_<hex>.exe or.cache_<hex>, chmods it 0755 on Unix, and spawns it detached via /bin/sh -c or cmd. Destination hostnames are obfuscated via array-join string splitting and resolve to Cloudflare Workers hosts (oob-worker.cf102-baf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-over-TXT fallback channel that queries c.<domain> and N.<domain> TXT records at sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, base64-decodes the concatenated chunks, and executes the reassembled binary. There is no hash or signature verification, and the delivery hosts are unpinned and attacker-controlled. Any process that imports this package triggers arbitrary remote code execution on the installer's machine.

## What should I do about MAL-2026-12554?

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-2026-12554 is a malicious package: checkout-desktop-bnpl (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-2026-12554/ (Markdown: https://insights.sbomify.com/MAL-2026-12554/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12554

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12554/
Summaries are generated and may contain mistakes; the official description above is the record.