PowerDNS Recursor before 3.1.5 uses insufficient randomness to calculate (1) TRXID values and (2) UDP source port numbers, which makes it easier for remote attackers to poison a DNS cache, related to (a) algorithmic deficiencies in rand and random functions in external libraries, (b) use of a 32-bit seed value, and (c) choice of the time of day as the sole seeding information.
https://www.redhat.com/archives/fedora-package-announce/2008-April/msg00224.html
https://www.redhat.com/archives/fedora-package-announce/2008-April/msg00198.html
https://exchange.xforce.ibmcloud.com/vulnerabilities/41534
http://www.vupen.com/english/advisories/2008/1046/references
http://www.securityfocus.com/bid/28517
http://www.securityfocus.com/archive/1/490330/100/0/threaded
http://www.debian.org/security/2008/dsa-1544
http://security.gentoo.org/glsa/glsa-200804-22.xml
http://secunia.com/advisories/30581
http://secunia.com/advisories/29830
http://secunia.com/advisories/29764
http://secunia.com/advisories/29737
http://lists.opensuse.org/opensuse-security-announce/2008-06/msg00001.html