In GLPI before version 9.4.6 there are multiple related stored XSS vulnerabilities. The package is vulnerable to Stored XSS in the comments of items in the Knowledge base. Adding a comment with content "" reproduces the attack. This can be exploited by a user with administrator privileges in the User-Agent field. It can also be exploited by an outside party through the following steps: 1. Create a user with the surname `" onmouseover="alert(document.cookie)` and an empty first name. 2. With this user, create a ticket 3. As an administrator (or other privileged user) open the created ticket 4. On the "last update" field, put your mouse on the name of the user 5. The XSS fires This is fixed in version 9.4.6.