There's a bug in the parser code for the "host.allow" element of login.conf(5). If you have more than one hostname in a comma separated argument to "host.allow=", and there's not a positive or negative match on the first element, sshd will infinitely loop because there's a missing strtok() to advance to the next field. The URL quoted above contains the cvs commit message I made to NetBSD-current to fix the problem there.
This is a NetBSD specific bug - neither OpenBSD nor portable OpenSSH have host.deny in login.conf.
Mass change of RESOLVED bugs to CLOSED