# MAL-2026-17760: Malicious code in @coopeuch/common (npm)


- **Type:** Malicious package
- **Package:** `@coopeuch/common` (npm)
- **Published:** 11 Oct 2026
- **Also known as:** GHSA-5h58-475h-6287

## What is MAL-2026-17760?

MAL-2026-17760 is a malicious package in @coopeuch/common, published on 11 Oct 2026. 

### Official description

@coopeuch/common@1.999.999 publishes to the public npm registry under a scope the publisher does not own, using an inflated version (1.999.999) consistent with the dependency-confusion technique that outranks internal-registry versions. The package's declared postinstall script (postinstall.js) runs automatically on npm install and collects installer-side host and network data — hostname, username, uid/gid, home directory, non-internal network interface addresses with MAC/CIDR, DNS resolver addresses, reverse-DNS internal FQDN, container markers, CI environment-variable presence, npm_config_registry, and the consuming project's package name/version/declared range — then POSTs it as JSON to the hardcoded author-controlled endpoint https://collector.oob.s4yhii.com/_npm-poc/beacon. A secondary DNS beacon is emitted via dns.lookup to a subdomain of oob.s4yhii.com. Any build that resolves @coopeuch/common from the public registry (including internal builds referencing the @coopeuch scope) will auto-exfiltrate internal hostnames, MAC addresses, usernames, internal registry URLs, and project identity to a third-party collector at install time. The package's README self-labels this as a coordinated-disclosure proof of concept; the harvesting and off-host upload nonetheless occur without installer opt-in.

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-2026-17760?

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-2026-17760 is a malicious package: @coopeuch/common (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-2026-17760/ (Markdown: https://insights.sbomify.com/MAL-2026-17760/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-17760

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-17760/
Summaries are generated and may contain mistakes; the official description above is the record.