DHCP starvation attacks are designed to deplete all of the addresses within the DHCP scope on a particular segment. Subsequently, a legitimate user is denied an IP address requested via DHCP and thus is not able to access the network. Yersinia is one such free hacking tool that performs automated DHCP starvation attacks. DHCP starvation may be purely a DoS mechanism or may be used in conjunction with a malicious rogue server attack to redirect traffic to a malicious computer ready to intercept traffic. Imagine a user filling up the dhcp pool and then re-directing users to their own DHCP server.
How do you fix this?
802.11 has several mechanisms built in. DHCP Proxy is one way. Port security is another. If you are running Mikrotik there are some scripts which can alert you to rogue DHCP servers, but that is an after-the-fact kind of thing.