The npm package 'cors-update' impersonates the legitimate 'cors' Express middleware but contains malicious code that fetches and executes attacker-controlled JavaScript code from a hardcoded URL. This execution occurs with full access to Node.js require, enabling arbitrary code execution in the host application. The malicious code disguises its network request as a blockchain RPC call and disables TLS verification, increasing risk. Applications that install and invoke this package as a substitute for 'cors' are vulnerable to remote code execution.