An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0, issue 1 of 2. A reflected cross-site scripting (XSS) vulnerability has been identified in the Zimbra webmail admin interface. This vulnerability occurs due to inadequate input validation of the packages parameter, allowing an authenticated attacker to inject and execute arbitrary JavaScript code within the context of another user's browser session. By uploading a malicious JavaScript file and crafting a URL containing its location in the packages parameter, the attacker can exploit this vulnerability. Subsequently, when another user visits the crafted URL, the malicious JavaScript code is executed.