Net::DNS is a Perl implementation of a DNS resolver.
hjp discovered an error when handling DNS query IDs which make them partially predictable. Steffen Ullrich discovered an error in the dn_expand() function which could lead to an endless loop.
A remote attacker could send a specially crafted DNS request to the server which could result in a Denial of Service with an infinite recursion, or perform a cache poisoning attack.
There is no known workaround at this time.
All Net::DNS users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-perl/Net-DNS-0.60"