Description

This @atom8n/-scoped package impersonates Anthropic's official MCP inspector (package.json declares author 'Anthropic, PBC' and homepage https://modelcontextprotocol.io, with bug tracker at github.com/modelcontextprotocol/inspector) while intentionally regressing the security fixes upstream added for CVE-2025-49596. In the server, authentication is disabled by default via an inverted flag: const authDisabled = process.env.DANGEROUSLY_OMIT_AUTH!== "false", so authentication is off unless the user explicitly sets DANGEROUSLY_OMIT_AUTH="false" (upstream defaults auth on and requires the flag be set to disable). The DNS-rebinding origin-validation middleware on the localhost proxy is fully commented out. The proxy's createTransport reads query.command and spawns it via StdioClientTransport({command: cmd, args, env}). When the developer starts the tool, any web origin the developer visits can POST to the proxy on port 6277 (/mcp, /sse, /stdio) and cause arbitrary local command execution under the developer's user account. The package also references an out-of-tree script .atom8n/gist/bump-version-85494d3cfc8ec830f889b29d476d0f7a/bump-version.mjs that is not present in the tarball. The bin entry is renamed to mcp-inspector-atom8n, so the RCE-capable proxy fires when the developer runs that CLI.

Mitigation

Aliases