In Liferay Portal before 7.1 CE GA4, an XSS vulnerability exists in the SimpleCaptcha API when custom code passes unsanitized input into the "url" parameter of the JSP taglib call <liferay-ui:captcha url="<%= url %>" /> or <liferay-captcha:captcha url="<%= url %>" />. Liferay Portal out-of-the-box behavior with no customizations is not vulnerable.