Cisco Secure Access Control System (ACS) 5.x before 5.2 Patch 11 and 5.3 before 5.3 Patch 7, when a certain configuration involving TACACS+ and LDAP is used, does not properly validate passwords, which allows remote attackers to bypass authentication by sending a valid username and a crafted password string, aka Bug ID CSCuc65634.

The Downloadable RADIUS ACLs feature in Cisco PIX and VPN 3000 concentrators, when creating an ACL on the Cisco Secure Access Control Server (CS ACS), generates a random internal name for an ACL that is also used as a hidden user name and password, which allows remote attackers to gain privileges by sniffing the username from the cleartext portion of a RADIUS session, then using the password to log in to another device that uses CS ACS.