From the Caldera security advisory: "Yet another ptrace race condition has been found which allows local
attackers to get access to the root account.
Also, a local attacker can use a recursive symlink structure setup
to effectively cause all filesystem actions to hang for an infinite
amount of time.
The IPTABLES implementation in the 2.4 kernel also had a problem in
the RELATED connection handling of the ip_conntrack_module which is
fixed by the supplied packages."