# MAL-2026-13261: Malicious code in devplatform-spa-plugin-s3-router (npm)


- **Type:** Malicious package
- **Package:** `devplatform-spa-plugin-s3-router` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-h72c-g9pj-cr88

## What is MAL-2026-13261?

MAL-2026-13261 is a malicious package in devplatform-spa-plugin-s3-router, published on 5 Aug 2026. 

### Official description

On require() of devplatform-spa-plugin-s3-router, index.js loads _helpers.js which runs a bootstrap routine at module load. The code assembles Cloudflare Workers hostnames (oob-worker.cf10-0-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) via string-splitting and.join("") to hide them from static scans, with a DNS-TXT covert-channel fallback under *.dl.wel1.ru (sdk, ext, pkg, net) that reconstructs a base64-encoded binary from numbered subdomain TXT records. The retrieved binary is written to /tmp or the Windows temp directory under a disguised name mimicking Microsoft dotnet diagnostics (dotnet_diag_<hex>.exe or.cache_<hex>), chmod 0755'd, and spawned detached via /bin/sh -c or cmd /c start. A.analytics_state file rate-limits re-execution. A sibling lib/telemetry.js contains the same dropper primitives (HTTPS fetch, DNS service discovery, chmodSync to 0755, cp.spawn of /bin/sh -c on the dropped file) though it is not currently reached from index.js. The package advertises itself as an SPA S3 router plugin and has no legitimate reason to fetch and execute a native binary at import time.

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-2026-13261?

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-2026-13261 is a malicious package: devplatform-spa-plugin-s3-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-2026-13261/ (Markdown: https://insights.sbomify.com/MAL-2026-13261/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-13261

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-13261/
Summaries are generated and may contain mistakes; the official description above is the record.