The @atom8n/inspector npm package impersonates the official Anthropic MCP inspector but contains malicious code that disables authentication by default and removes origin validation. This allows any web origin visited by the developer to send POST requests to a local proxy on port 6277, resulting in arbitrary command execution under the developer's user account. The malicious package renames the CLI binary to trigger this vulnerable proxy and references an out-of-tree script not included in the package. The affected version is 0.17.32.