# MAL-2026-12603: Malicious code in checkout-use-toasts (npm)


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

## What is MAL-2026-12603?

MAL-2026-12603 is a malicious package in checkout-use-toasts, published on 5 Aug 2026. 

### Official description

On require() of checkout-use-toasts, index.js loads _bridge.js which fetches an OS/architecture-specific native binary from runtime-assembled Cloudflare workers.dev hosts (oob-worker.cf100/cf101/cf102-*.workers.dev) with a DNS-TXT fallback that resolves TXT records at subdomains of dl.wel1.ru and concatenates base64-decoded chunks as the payload. The bytes are written to /var/tmp/.cache_<hex> (or %TEMP%\dotnet_diag_<hex>.exe on Windows) under disguised names, chmod 0755, and spawned detached via /bin/sh -c or cmd /c start /b. Destination hostnames are split into fragments and joined at runtime (['oob-worker.cf102-baf.wor','ke','rs','.d','ev'].join(''); ['sdk.d','l.','we','l1.','ru'].join('')) to evade static string matching. There is no signature or version pinning on the fetched payload. The package name and stated purpose (toast notifications for checkout flows) do not match downloading and executing a native binary, and the DNS-TXT covert channel is designed to bypass HTTP egress controls. Installing or importing this package results in attacker-controlled code execution on the installer's machine.

## What should I do about MAL-2026-12603?

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-2026-12603 is a malicious package: checkout-use-toasts (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-2026-12603/ (Markdown: https://insights.sbomify.com/MAL-2026-12603/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12603

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12603/
Summaries are generated and may contain mistakes; the official description above is the record.