An issue was discovered in Zimbra Collaboration (ZCS) through v10.1. A Cross-Site Scripting (XSS) vulnerability exists in one of the endpoints of Zimbra Webmail due to insufficient sanitization of the packages parameter. Attackers can bypass the existing checks by using encoded characters, allowing the injection and execution of arbitrary JavaScript within a victim's session.
https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy
https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P41#Security_Fixes
https://wiki.zimbra.com/wiki/Zimbra_Releases/8.8.15/P46#Security_Fixes
https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.1#Security_Fixes
https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.9#Security_Fixes