libdns in ISC BIND 9.7.x and 9.8.x before 9.8.4-P2, 9.8.5 before 9.8.5b2, 9.9.x before 9.9.2-P2, and 9.9.3 before 9.9.3b2 on UNIX platforms allows remote attackers to cause a denial of service (memory consumption) via a crafted regular expression, as demonstrated by a memory-exhaustion attack against a machine running a named process.