NCP Secure Enterprise Client (aka VPN/PKI client) 8.30 Build 59, and possibly earlier versions, when the Link Firewall and Personal Firewall are both configured to block all inbound and outbound network traffic, allows context-dependent attackers to send inbound UDP traffic with source port 67 and destination port 68, and outbound UDP traffic with source port 68 and destination port 67.

Client Firewall in NCP Network Communication Secure Client 8.11 Build 146, and possibly other versions, allows local users to bypass firewall program execution rules by replacing an allowed program with an arbitrary program.

NCP Network Communication Secure Client 8.11 Build 146, and possibly other versions, allows local users to bypass security protections and configure privileged options via a long argument to ncpmon.exe, which provides access to alternate privileged menus, possibly due to a buffer overflow.

NCP Network Communication Secure Client 8.11 Build 146, and possibly other versions, allows local users to cause a denial of service (CPU consumption) via a large number of arguments to ncprwsnt.exe, possibly due to a buffer overflow.

NCP Network Communication Secure Client 8.11 Build 146, and possibly other versions, allows local users to cause a denial of service (memory usage and cpu utilization) via a flood of arbitrary UDP datagrams to ports 0 to 65000. NOTE: this issue was reported as a buffer overflow, but that term usually does not apply in flooding attacks.

The ncprwsnt service in NCP Network Communication Secure Client 8.11 Build 146, and possibly other versions, allows local users to execute arbitrary code by modifying the connect.bat script, which is automatically executed by the service after a connection is established.