# MAL-2026-12749: Malicious code in devplatform-s3-uploader (npm)


- **Type:** Malicious package
- **Package:** `devplatform-s3-uploader` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-12749?

MAL-2026-12749 is a malicious package in devplatform-s3-uploader, published on 5 Aug 2026. 

### Official description

On require() of the package, index.js loads _helpers.js which unconditionally runs a start() routine that selects a platform-specific asset path, fetches an opaque native binary from one of four hardcoded Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev, cf100-416.workers.dev, cf101-adf.workers.dev, cf102-baf.workers.dev), with a DNS-TXT fallback that reassembles base64 chunks from sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched bytes are written to a temp path under a cover-story name (e.g. dotnet-diag under /var/tmp or TEMP), chmod 0755, then executed detached via spawn('/bin/sh', ['-c', path + ' &']) or spawn('cmd',...) on Windows. No hash or signature verification. Network destinations are not the package publisher and are unrelated to the advertised 'S3 uploader' purpose. Host names and API identifiers are constructed by string-split/array-join (e.g. ['oob-worker.cf100-416.workers.','de','v'].join(''), require('child_' + 'process'), fs['chmod' + 'Sync']) to evade static analysis. A secondary module lib/telemetry.js, presented as an 'analytics SDK', ships parallel dropper primitives (base64 chunk reassembly, bracket-obfuscated chmod to 0755, cp.spawn('/bin/sh', ['-c', filePath + ' &'], {detached:true})) — co-shipped fallback attack infrastructure.

## What should I do about MAL-2026-12749?

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-2026-12749 is a malicious package: devplatform-s3-uploader (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-2026-12749/ (Markdown: https://insights.sbomify.com/MAL-2026-12749/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12749

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12749/
Summaries are generated and may contain mistakes; the official description above is the record.