Reflected Cross-Site Scripting (XSS) Vulnerabilities on Scriptcase

I scanned the scriptcase app with Qualys Scan (Vulnerability scan management) and I see Level 5 security vulnerability: Reflected Cross-Site Scripting (XSS) Vulnerabilities How to fix these Vulnerabilities?

Everything about Cross-Site Scripting (XSS)

Everything about Cross-Site Scripting (XSS)

10 Practical scenarios for XSS attacks

Uncovering Attacks: Cross-site Scripting (XSS)

Reflected Cross-Site Scripting (XSS) Vulnerabilities on Scriptcase

Types of XSS (Cross-site Scripting)

10 Practical scenarios for XSS attacks

What is Cross-site Scripting and How Can You Fix it?

10 Practical scenarios for XSS attacks