An improper certificate validation vulnerability [CWE-295] in FortiOS 6.0.0 through 6.0.14, 6.2.0 through 6.2.10, 6.4.0 through 6.4.8, 7.0.0 may allow a network adjacent and unauthenticated attacker to man-in-the-middle the communication between the FortiGate and some peers such as private SDNs and external cloud platforms.