1st-Party script

First-party scripts are pieces of JavaScript served directly from a website's own domain. They're typically under the control of that site's development team, making them simpler to audit and manage. Because the site itself hosts them, administrators can use internal code reviews, version control, and strict security headers (such as Content Security Policy) to reduce vulnerabilities. However, even first-party scripts may contain security flaws due to dependency chains, which are typically compiled via a package manager. In a client-side security context, properly vetting and updating first-party code is crucial to defending against attacks like cross-site scripting (XSS) and data exfiltration.