Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
It was found in all keycloak versions before 9.0.0 that links to external applications (Application Links) in the admin console are not validated properly and could allow Stored XSS attacks. An authed malicious user could create URLs to trick users in other realms, and possibly conduct further attacks.
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.