CVE-2001-0183

CVE-2001-0183 describes a vulnerability in FreeBSD's ipfw and ip6fw firewall components (versions 4.2 and earlier) that allows remote attackers to bypass access restrictions. By setting the ECE flag in a TCP packet, an attacker can make the packet appear to be part of an established connection, thereby circumventing firewall rules. This vulnerability has a CVSS score of 7.5 (HIGH), indicating a high-severity issue with a network attack vector, low complexity, and potential for partial compromise of confidentiality, integrity, and availability. While not listed on the KEV catalog or Hot List, an exploit (EDB-20593) is publicly available, though there is no evidence of active exploitation or significant community discussion.