Unbound before 1.4.13p2 attempts to free unallocated memory during processing of duplicate CNAME records in a signed zone, which allows remote DNS servers to cause a denial of service (daemon crash) via a crafted response.
lists.fedoraproject.org/pipermail/package-announce/2012-January/071525.html
lists.fedoraproject.org/pipermail/package-announce/2012-January/071535.html
osvdb.org/77909
secunia.com/advisories/47326
unbound.nlnetlabs.nl/downloads/CVE-2011-4528.txt
www.debian.org/security/2011/dsa-2370
www.kb.cert.org/vuls/id/209659