A missing release of memory after its effective lifetime vulnerability in the Webmail of FortiMail 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6 may allow an unauthenticated remote attacker to exhaust available memory via specifically crafted login requests.

The combination of various cryptographic issues in the session management of FortiMail 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6, including the encryption construction of the session cookie, may allow a remote attacker already in possession of a cookie to possibly reveal and alter or forge its content, thereby escalating privileges.