A FreeBSD patch for SSH on 2000-01-14 configures ssh to listen on port 722 as well as port 22, which might allow remote attackers to access SSH through port 722 even if port 22 is otherwise filtered.
The undocumented semconfig system call in BSD freezes the state of semaphores, which allows local users to cause a denial of service of the semaphore system by using the semconfig call.
Vulnerability when Network Address Translation (NAT) is enabled in Linux 2.2.10 and earlier with ipchains, or FreeBSD 3.2 with ipfw, allows remote attackers to cause a denial of service (kernel panic) via a ping -R (record route) command.