Netbsd : Security Vulnerabilities, CVEs, Published In 2001 (Denial of service)

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.

sendmsg function in NetBSD 1.3 through 1.5 allows local users to cause a denial of service (kernel trap or panic) via a msghdr structure with a large msg_controllen length.

NetBSD 1.5 and earlier and FreeBSD 4.3 and earlier allows a remote attacker to cause a denial of service by sending a large number of IP fragments to the machine, exhausting the mbuf pool.