Net::DNS before 0.60, a Perl module, allows remote attackers to cause a denial of service (stack consumption) via a malformed compressed DNS packet with self-referencing pointers, which triggers an infinite loop.
Header.pm in Net::DNS before 0.60, a Perl module, (1) generates predictable sequence IDs with a fixed increment and (2) can use the same starting ID for all child processes of a forking server, which allows remote attackers to spoof DNS responses, as originally reported for qpsmtp and spamassassin.