Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The Simple SEO plugin for WordPress is vulnerable to attribute-based stored Cross-Site Scripting in versions up to, and including 1.7.91, due to insufficient sanitization or escaping on the SEO social and standard title parameters. This can be exploited by authenticated users with Contributor and above permissions to inject arbitrary web scripts into posts/pages that execute whenever an administrator access the page.
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.