CVE 2012-0024
MaraDNS before 1.3.07.12 and 1.4.x before 1.4.08 computes hash values for DNS data without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted queries with the Recursion Desired (RD) bit set.
See the
CVE page on Mitre.org
for more details.