iterator.c in NLnet Labs Unbound before 1.5.1 does not limit delegation chaining, which allows remote attackers to cause a denial of service (memory and CPU consumption) via a large or infinite number of referrals.
https://unbound.net/downloads/CVE-2014-8602.txt
http://www.ubuntu.com/usn/USN-2484-1
http://www.securityfocus.com/bid/71589
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
http://www.kb.cert.org/vuls/id/264212
http://www.debian.org/security/2014/dsa-3097