Multiple cross-site scripting (XSS) vulnerabilities in the web-authentication function on the Cisco NAC Appliance 4.9.2 and earlier allow remote attackers to inject arbitrary web script or HTML via the (1) cm or (2) uri parameters to (a) perfigo_weblogin.jsp, or the (3) cm, (4) provider, (5) session, (6) uri, (7) userip, or (8) username parameters to (b) perfigo_cm_validate.jsp, aka Bug ID CSCud15109.

Cisco NAC maintains an exception list that does not record device properties other than MAC address, which allows physically proximate attackers to bypass control methods and join a local network by spoofing the MAC address of a different type of device, as demonstrated by using the MAC address of a disconnected printer.

Cisco NAC allows quarantined devices to communicate over the network with (1) DNS, (2) DHCP, and (3) EAPoUDP, which allows attackers to bypass control methods by tunneling network traffic through one of these protocols.