Zero-Day Advisory

Fortinet Discovers Zimbra Collaboration Chat Cross-Site Scripting Vulnerability


Fortinet's FortiGuard Labs has discovered a Cross-Site Scripting (XSS) vulnerability in Zimbra Collaboration.

Zimbra Collaboration is an open, secure collaboration software suite for email, address book, calendar, file-sharing and tasks. According to its website, there are over 500 million people who are using Zimbra Collaboration and come from 135+ countries. Zimbra Collaboration is used by 500+ service providers, 1000+ government & financial institutions and 200k+ businesses.

A XSS vulnerability has been discovered in Zimbra Collaboration. The vulnerability is caused due to insufficiently sanitizing Chat user name content. It allows remote attackers to launch XSS attack against Zimbra Collaboration users.


FortiGuard Labs released the following FortiGate IPS signature which covers this specific vulnerability:

Released Nov 06, 2017

Users should apply the solution provided by Zimbra.


Fortinet reported the vulnerability to Zimbra on November 2, 2017.

Zimbra confirmed the vulnerability on November 6, 2017.

Zimbra patched the vulnerability on December 12, 2017.


This vulnerability was discovered by Zhouyuan Yang of Fortinet's FortiGuard Labs.

IPS Subscription

Fortinet customers who subscribe to Fortinet's intrusion prevention (IPS) service should be protected against this vulnerability with the appropriate configuration parameters in place. Fortinet's IPS service is one component of FortiGuard Subscription Services, which also offer comprehensive solutions such as antivirus, Web content filtering and antispam capabilities. These services enable protection against threats on both application and network layers. FortiGuard Services are continuously updated by FortiGuard Labs, which enables Fortinet to deliver a combination of multi-layered security intelligence and true zero-day protection from new and emerging threats. These updates are delivered to all FortiGate, FortiMail and FortiClient products. Fortinet strictly follows responsible disclosure guidelines to ensure optimum protection during a threat's lifecycle.