Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The WP YouTube Lyte WordPress plugin before 1.7.16 did not sanitise or escape its lyte_yt_api_key and lyte_notification settings before outputting them back in the page, allowing high privilege users to set XSS payload on them and leading to stored Cross-Site Scripting issues.
CWE-79 - Cross Site Scripting
Cross-Site Scripting, commonly referred to as XSS, is the most dominant class of vulnerabilities. It allows an attacker to inject malicious code into a pregnable web application and victimize its users. The exploitation of such a weakness can cause severe issues such as account takeover, and sensitive data exfiltration. Because of the prevalence of XSS vulnerabilities and their high rate of exploitation, it has remained in the OWASP top 10 vulnerabilities for years.