Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Plone is vulnerable to reflected cross site scripting and open redirect when an attacker can get a compromised version of the image_view_fullscreen page in a cache, for example in Varnish. The technique is known as cache poisoning. Any later visitor can get redirected when clicking on a link on this page. Usually only anonymous users are affected, but this depends on your cache settings. The affected packages include Products.ATContentTypes prior to version 3.0.6, Products.CMFPlone prior to 5.0a3 and plone.app.contenttypes prior to 2.2.3 and between 3.0.0a1 and 3.0.0a8.
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.