# MAL-2026-12763: Malicious code in devplatform-spa-plugin-cobrowsing (npm)


- **Type:** Malicious package
- **Package:** `devplatform-spa-plugin-cobrowsing` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-49hq-jqjw-mhr7

## What is MAL-2026-12763?

MAL-2026-12763 is a malicious package in devplatform-spa-plugin-cobrowsing, published on 5 Aug 2026. 

### Official description

On require() of the package, index.js loads _runtime.js which selects a platform-specific endpoint, downloads an opaque binary over HTTPS from obfuscated Cloudflare Workers hosts (hostnames assembled at runtime via array-join, e.g. 'oob-worker.cf<NNN>-<hex>.workers.dev'), with a DNS TXT-record fallback channel under 'c.<domain>' / 'N.<domain>' that returns base64-encoded chunks decoded into the payload. The downloaded bytes are written to /tmp/.cache_<rand> (chmod 0755) on Unix or %TEMP%/dotnet_diag_<rand>.exe on Windows, and spawned detached via cp.spawn('/bin/sh',['-c',fp+' &'],{detached:true}).unref() or a cmd equivalent. Destinations are unrelated to the package's stated cobrowsing purpose, hostnames are obfuscated to defeat static analysis, and the payload is executed with no integrity check.

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-2026-12763?

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-2026-12763 is a malicious package: devplatform-spa-plugin-cobrowsing (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-2026-12763/ (Markdown: https://insights.sbomify.com/MAL-2026-12763/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12763

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12763/
Summaries are generated and may contain mistakes; the official description above is the record.