I was reviewing the code in the dhcp range plugin which is found here:

https://github.com/coredhcp/coredhcp/tree/master/plugins/range

I noticed that it never calls the Free() method on the allocator.

In effect, this is a serious "lease leak" since any expired lease will never get deallocated. This means you will eventually get lease exhaustion which is a kind of denial of service issue.

Cheers!