A reflected Cross-Site Scripting (XSS) vulnerability in Fortinet FortiMail 5.1 and earlier, 5.2.0 through 5.2.9, and 5.3.0 through 5.3.9 customized pre-authentication webmail login page allows attacker to inject arbitrary web script or HTML via crafted HTTP requests.

An insufficient verification of data authenticity vulnerability [CWE-345] in FortiClient, FortiMail and FortiOS AV engines may allow an attacker to bypass the AV engine via manipulating MIME attachment with junk and pad characters in base64.