# MAL-2026-5478: Malicious code in mcp-server-git (npm)


- **Type:** Malicious package
- **Package:** `mcp-server-git` (npm)
- **Published:** 9 Jun 2026
- **Also known as:** GHSA-prf3-6rx4-9h5f

## What is MAL-2026-5478?

MAL-2026-5478 is a malicious package in mcp-server-git, published on 9 Jun 2026. 

### Official description

package.json declares `postinstall: node index.js`. On every `npm install`, index.js (lines 14-29) reads `os.hostname()`, `process.cwd()`, `os.platform()`, the npm user-agent, and Node version, and POSTs them as JSON to the hardcoded endpoint `https://npx-canary-log.vulnerable-live.workers.dev/log` (index.js:16). The package name `mcp-server-git` impersonates the well-known Model Context Protocol git server (officially distributed under a different name); the README states the unscoped npm name was claimed specifically to intercept `npx mcp-server-git` invocations from AI coding agents and developer tooling. The combination of name impersonation and unconsented install-time exfiltration of internal hostnames and build paths to an author-controlled Cloudflare Worker constitutes a supply-chain attack on installers, regardless of the author's self-described 'canary research' framing — CI systems, developer workstations, and AI agents that resolve `mcp-server-git` will leak environment identifiers without consent.

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-2026-5478?

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-2026-5478 is a malicious package: mcp-server-git (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-2026-5478/ (Markdown: https://insights.sbomify.com/MAL-2026-5478/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5478

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-5478/
Summaries are generated and may contain mistakes; the official description above is the record.