Cisco VPN 3000 Concentrator 2.2.x, and 3.x before 3.5.3, allows remote attackers to obtain potentially sensitive information without authentication by directly accessing certain HTML pages.

Cisco Virtual Private Network (VPN) Client software 2.x.x, and 3.x before 3.5.1C, allows local users to use a utility program to obtain the group password.

Cisco VPN 3000 Concentrator 2.2.x, and 3.x before 3.5.3, allows remote attackers to cause a denial of service (crash) via a long (1) username or (2) password to the HTML login interface.

Cisco Virtual Private Network (VPN) Client software 2.x.x, and 3.x before 3.5.2B, does not generate sufficiently random numbers, which may make it vulnerable to certain attacks such as spoofing.

Cisco Virtual Private Network (VPN) Client software 2.x.x, and 3.x before 3.6(Rel), when configured with all tunnel mode, can be forced into acknowledging a TCP packet from outside the tunnel.

Cisco VPN 3000 Concentrator 2.2.x, and 3.x before 3.5.3, adds an "HTTPS on Public Inbound (XML-Auto)(forward/in)" rule but sets the protocol to "ANY" when the XML filter configuration is enabled, which ultimately allows arbitrary traffic to pass through the concentrator.

Cisco VPN 3000 Concentrator 2.2.x, 3.6(Rel), and 3.x before 3.5.5, allows remote attackers to cause a denial of service via a long user name.

The LAN-to-LAN IPSEC capability for Cisco VPN 3000 Concentrator 2.2.x, and 3.x before 3.5.4, allows remote attackers to cause a denial of service via an incoming LAN-to-LAN connection with an existing security association with another device on the remote network, which causes the concentrator to remove the previous connection.

Cisco Virtual Private Network (VPN) Client software 2.x.x, and 3.x before 3.5.1C, does not properly verify that certificate DN fields match those of the certificate from the VPN Concentrator, which allows remote attackers to conduct man-in-the-middle attacks.

Buffer overflows in Cisco Virtual Private Network (VPN) Client 3.5.4 and earlier allows remote attackers to cause a denial of service via (1) an Internet Key Exchange (IKE) with a large Security Parameter Index (SPI) payload, or (2) an IKE packet with a large number of valid payloads.