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 3.5.1C, 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.

Unspecified vulnerability in the VPN Client for Windows Graphical User Interface (GUI) (aka the VPN client dialer) in Cisco VPN Client for Windows 4.8.00. and earlier, except for 4.7.00.0533, allows local authenticated, interactive users to gain privileges, possibly due to privileges of dialog boxes, aka bug ID CSCsd79265.

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 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.

The StartServiceCtrlDispatcher function in the cvpnd service (cvpnd.exe) in Cisco VPN client for Windows before 5.0.06.0100 does not properly handle an ERRORFAILEDSERVICECONTROLLERCONNECT error, which allows local users to cause a denial of service (service crash and VPN connection loss) via a manual start of cvpnd.exe while the cvpnd service is running.