An authentication and access control bypass vulnerability exists in the web server management interface of Brocade Fabric OS versions before 10.0.1. The web dispatcher routine evaluates internal management VLAN trust decisions using the client-supplied HTTP host header instead of the actual socket transport layer source IP address. Successful exploitation allows the attacker to bypass IP-filtering access control lists (ACLs) and obtain sensitive device metadata (such as model, serial number, hardware revision, and firmware version) without authentication.