CVE-2001-1431: Check Point Firewall-1

Medium severity, CVSS 5.0. EPSS: 1.3% chance of exploitation in the next 30 days.

Nokia Firewall Appliances running IPSO 3.3 and VPN-1/FireWall-1 4.1 Service Pack 3, IPSO 3.4 and VPN-1/FireWall-1 4.1 Service Pack 4, and IPSO 3.4 or IPSO 3.4.1 and VPN-1/FireWall-1 4.1 Service Pack 5, when SYN Defender is configured in Active Gateway mode, does not properly rewrite the third packet of a TCP three-way handshake to use the NAT IP address, which allows remote attackers to gain sensitive information.

Affected products

• Check Point Firewall-1: version 4.1 only
• Check Point VPN-1: version 4.1 only
• Nokia Firewall Appliance: version ipso_3.3 only; version ipso_3.4 only; version ipso_3.41 only

Published 2001-10-08. Last modified 2026-06-16.