All computers with existing versions of LinuxPPC installed are accessible as root by anyone if they are able to boot the machine in single user mode. A DoS attack using malformed TCP packets can pause bind.
Several bugs can cause the server to crash due to remote attacks.
If you are running bind it is recommended that you upgrade immediately. It is recommended that LinuxPPC users running NIS upgrade as soon as possible. Also, lpr doesn't do any checks before opening queued files as root which could allow somone to symlink to a file and print it regardless of access permissions. In certain network configurations pam may allow access to locked NIS accounts. Samba users should upgrade as soon as possible.