CVE-2006-3551: Ncp Network Communications Secure Client

Low severity, CVSS 1.2. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Ncp Network Communications Secure Client: up to and including 8.30_build_59

Published 2006-07-13. Last modified 2026-06-16.