The DNSPacket::expand method in dnspacket.cc in PowerDNS before 2.9.17 allows remote attackers to cause a denial of service by sending a random stream of bytes.
https://exchange.xforce.ibmcloud.com/vulnerabilities/19221
http://www.securityfocus.com/bid/12446
http://www.gentoo.org/security/en/glsa/glsa-200502-15.xml