Linux : Security Vulnerabilities, CVEs, Published In July 2001

Multiple TCP implementations could allow remote attackers to cause a denial of service (bandwidth and CPU exhaustion) by setting the maximum segment size (MSS) to a very small number and requesting large amounts of data, which generates more packets with less TCP-level data that amplify network traffic and consume more server CPU to process.

IRC DCC helper in the ip_masq_irc IP masquerading module 2.2 allows remote attackers to bypass intended firewall restrictions by causing the target system to send a "DCC SEND" request to a malicious server which listens on port 6667, which may cause the module to believe that the traffic is a valid request and allow the connection to the port specified in the DCC SEND request.

ip_conntrack_ftp in the IPTables firewall for Linux 2.4 allows remote attackers to bypass access restrictions for an FTP server via a PORT command that lists an arbitrary IP address and port number, which is added to the RELATED table and allowed by the firewall.