A improper verification of cryptographic signature vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, 7.4.0 7.4.8, 7.2.0 7.2.11, 7.0.0 7.0.17, FortiProxy 7.4.10, 7.2.14, 7.0.21, FortiSwitchManager 7.2.6, 7.0.5 allows an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML response message.