The issue is related to the FortiManager protocol service in Fortinet FortiOS, which does not prevent the use of anonymous ciphersuites. This makes it easier for man-in-the-middle attackers to obtain sensitive information or interfere with communications by modifying the client-server data stream. The vulnerability can be exploited by a remote attacker to perform a man-in-the-middle attack, gain access to protected information, and redirect network traffic.