CVE-2001-0183: Freebsd

High severity, CVSS 7.5. EPSS: 8.1% chance of exploitation in the next 30 days.

ipfw and ip6fw in FreeBSD 4.2 and earlier allows remote attackers to bypass access restrictions by setting the ECE flag in a TCP packet, which makes the packet appear to be part of an established connection.

Affected products

• Freebsd Freebsd: version 3.0 only; version 3.1 only; version 3.3 only; version 3.4 only; version 3.5 only; version 3.5.1 only; …

Published 2001-03-26. Last modified 2026-06-16.