The new version fixes a DoS in leafnode that can occur with the default settings. Although this bug is remotly exploitable, it's doesn't allow remote privilege escalation.
Created attachment 23456 [details] leafnode-1.9.48.ebuild Please take a good look at #36368 - because there are changes between the ebuild in portage and this one.
BTW: There is already a new version.
1.9.49 (x86) and .50 (~x86) already committed to the tree. .42 will be deprecated shortly.