An issue was discovered in GFI Kerio Control 9.2.5 through 9.4.5. The dest GET parameter passed to the /nonauth/addCertException.cs and /nonauth/guestConfirm.cs and /nonauth/expiration.cs pages is not properly sanitized before being used to generate a Location HTTP header in a 302 HTTP response. This can be exploited to perform Open Redirect or HTTP Response Splitting attacks, which in turn lead to Reflected Cross-Site Scripting (XSS). Remote command execution can be achieved by leveraging the upgrade feature in the admin interface.