An issue was discovered in Zimbra Collaboration (ZCS) through 10.0. Zimbra Webmail (Modern UI) is vulnerable to a stored Cross-Site Scripting (XSS) attack due to improper sanitization of user input. This allows an attacker to inject malicious code into specific fields of an e-mail message. When the victim adds the attacker to their contacts, the malicious code is stored and executed when viewing the contact list. This can lead to unauthorized actions such as arbitrary mail sending, mailbox exfiltration, profile picture alteration, and other malicious actions. Proper sanitization and escaping of input fields are necessary to mitigate this vulnerability.
An issue was discovered in Zimbra Collaboration (ZCS) through 10.1. A reflected Cross-Site Scripting (XSS) issue exists through the Briefcase module due to improper sanitization of file content by the OnlyOffice formatter. This occurs when the victim opens a crafted URL pointing to a shared folder containing a malicious file uploaded by the attacker. The vulnerability allows the attacker to execute arbitrary JavaScript in the context of the victim's session.