http://nvd.nist.gov/nvd.cfm?cvename=CVE-2006-6301

"DenyHosts 2.5 does not properly parse sshd logs file, which allows remote
attackers to add arbitrary hosts to the /etc/hosts.deny file and cause a denial
of service by adding arbitrary IP addresses to the sshd log file, as
demonstrated by loggig in to ssh using a login name containing certain strings
with an IP address, which is not properly handled by a regular expression."

Based on version numbers, affects FE-3+ and EPEL-4+