AEM's Cloud Service offering, as well as version 6.5.10.0 (and below) are affected by a reflected Cross-Site Scripting (XSS) vulnerability via the itemResourceType parameter. If an attacker is able to convince a victim to visit a URL referencing a vulnerable page, malicious JavaScript content may be executed within the context of the victim's browser
https://helpx.adobe.com/security/products/experience-manager/apsb21-103.html