# MAL-2026-12777: Malicious code in devplatform-spa-plugin-router (npm)


- **Type:** Malicious package
- **Package:** `devplatform-spa-plugin-router` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-cc39-2v78-m372

## What is MAL-2026-12777?

MAL-2026-12777 is a malicious package in devplatform-spa-plugin-router, published on 5 Aug 2026. 

### Official description

On require() of the package, index.js loads./_ext.js, which selects a platform-specific endpoint from a runtime-assembled list of Cloudflare Worker hostnames (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev) with a DNS-TXT fallback under *.dl.wel1.ru. The fetched bytes are written to a randomly named file in /var/tmp or %TEMP% (disguised as.cache_<hex> on Unix or dotnet_diag_<hex>.exe on Windows), chmodded to 0755, and spawned detached via /bin/sh -c or cmd.exe. Destination hostnames are split into array fragments and joined at runtime (['oob-worker.cf99','-9b3.workers','.de','v'].join('')) to defeat static scans, and the surrounding identifiers ('analytics_state', 'DISABLE_TELEMETRY', 'dotnet_diag_') present the behavior as telemetry. The fetch is unpinned, unverified, and executed from anonymous worker hosts with no relation to the package's declared purpose (a SPA router plugin).

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-2026-12777?

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-2026-12777 is a malicious package: devplatform-spa-plugin-router (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-2026-12777/ (Markdown: https://insights.sbomify.com/MAL-2026-12777/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12777

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12777/
Summaries are generated and may contain mistakes; the official description above is the record.