Forcepoint Next Generation Firewall (Forcepoint NGFW) 6.4.x before 6.4.7, 6.5.x before 6.5.4, and 6.6.x before 6.6.2 has a serious authentication vulnerability that potentially allows unauthorized users to bypass password authentication and access services protected by the NGFW Engine. The vulnerability affects the following NGFW features when the LDAP authentication method is used as the backend authentication: IPsec VPN, SSL VPN or Browser-based user authentication. The vulnerability does not apply when any other backend authentication is used. The RADIUS authentication method is not vulnerable, for example.