Reflected XSS, or Reflected Cross-Site Scripting, is a type of security vulnerability found in web applications. It occurs when an attacker sends a malicious script to a user, often through a URL. When the user clicks the link, the script is reflected off the web server and executed in their browser, potentially stealing sensitive information like cookies or login credentials. This attack relies on the user’s interaction with the malicious link, making it crucial for web developers to validate and sanitize user inputs. By doing so, they can prevent harmful scripts from being executed, protecting users from cyber threats and ensuring a safer online experience.