# MAL-2026-4537: Malicious code in cosmosdb-server (npm)


- **Type:** Malicious package
- **Package:** `cosmosdb-server` (npm)
- **Published:** 23 May 2026

## What is MAL-2026-4537?

MAL-2026-4537 is a malicious package in cosmosdb-server, published on 23 May 2026. 

### Official description

Package squats the unscoped name `cosmosdb-server`, targeting users who mistype `npx cosmosdb-server` instead of the scoped `@vercel/cosmosdb-server`. The package.json declares `bin: {"cosmosdb-server": "./index.js"}` and self-describes as a 'bin-mismatch PoC' for the Vercel package. When invoked (via `npx`, `bin` execution, or `require()`), index.js collects `os.hostname()`, `process.cwd()`, `process.platform`, `process.arch`, and a timestamp and POSTs them to a hardcoded endpoint at `https://callback-monitor.cyb3rsh4ykh.workers.dev/c`, controlled by the package author. The 'security research / responsible disclosure' framing in the description does not constitute installer consent — the package is published live on the public registry under a name designed to capture mistyped invocations, and victims have no opportunity to opt out before their host identity and working-directory path are exfiltrated. Combination of (a) ≤2-edit name confusion against a scoped Vercel package, (b) hardcoded attacker-controlled exfil endpoint, and (c) immediate-on-execution data collection meets the typosquat-with-installer-harm threshold.

## What should I do about MAL-2026-4537?

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-2026-4537 is a malicious package: cosmosdb-server (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-2026-4537/ (Markdown: https://insights.sbomify.com/MAL-2026-4537/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4537

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-4537/
Summaries are generated and may contain mistakes; the official description above is the record.