Description
Cross-site Scripting (XSS) refers to client-side code injection attack wherein an attacker can execute malicious scripts into a legitimate website or web application. XSS occurs when a web application makes use of unvalidated or unencoded user input within the output it generates.
Remediation
Apply context-dependent encoding and/or validation to user input rendered on a page
References
Cross-site Scripting (XSS) Attack - Acunetix
XSS Filter Evasion Cheat Sheet
Excess XSS, a comprehensive tutorial on cross-site scripting
Related Vulnerabilities
WordPress Plugin WordPress.com Custom CSS Cross-Site Scripting (1.5)
WordPress Plugin WordPress Download Manager Multiple Vulnerabilities (2.9.49)
Drupal Core 8.9.x Cross-Site Scripting (8.9.0 - 8.9.15)
WordPress Plugin Icon Widget Cross-Site Scripting (1.2.6)
WordPress Plugin Google Sitemap by BestWebSoft Cross-Site Scripting (2.9.1)