AEM versions 6.5.5.0 (and below), 6.4.8.1 (and below), 6.3.3.8 (and below) and 6.2 SP1-CFP20 (and below) are affected by an HTML injection vulnerability in the content editor component that allows unauthenticated users to craft an HTTP request that includes arbitrary HTML code in a parameter value. An attacker could then use the malicious GET request to lure victims to perform unsafe actions in the page (ex. phishing).
https://helpx.adobe.com/security/products/experience-manager/apsb20-56.html