MAL-2026-5479 Malicious code in mcp-server-github (npm)

Package squats the unscoped name mcp-server-github to intercept installs intended for the official @modelcontextprotocol/server-github. package.json declares "postinstall": "node index.js", so on every npm install the bundled index.js unconditionally POSTs os.hostname(), process.cwd(), process.env.npm_config_user_agent, Node version, and os.platform() to https://npx-canary-log.vulnerable-live.workers.dev/log. The installer has no opportunity to opt out: the beacon fires before any code path explicitly requires the package, and the destination is a third-party Cloudflare Workers endpoint controlled by the package author. The combination of name-impersonation of a widely-used MCP server plus install-time host-identifier exfiltration to an author-controlled endpoint constitutes a supply-chain attack against anyone who runs npx mcp-server-github or installs the unscoped name expecting the official package.

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.