What is XSS?

Cross-Site Scripting (XSS) is a type of security vulnerability typically found in web applications. It enables attackers to inject client-side scripts (usually JavaScript) into web pages viewed by other users. An attacker can use XSS to bypass access controls such as the same-origin policy. XSS vulnerabilities are commonly exploited to steal cookies, redirect users to malicious websites, deface websites, or inject malware.