unbound - security update

Florian Maury from ANSSI discovered that unbound, a validating,
recursive, and caching DNS resolver, was prone to a denial of service
vulnerability. An attacker crafting a malicious zone and able to emit
(or make emit) queries to the server can trick the resolver into
following an endless series of delegations, leading to resource
exhaustion and huge network usage.

For Debian 6 Squeeze, these issues have been fixed in unbound version 1.4.6-1+squeeze4