Unspecified vulnerability in ISC BIND 9.0.x through 9.3.x, 9.4 before 9.4.3-P4, 9.5 before 9.5.2-P1, 9.6 before 9.6.1-P2, and 9.7 beta before 9.7.0b3, with DNSSEC validation enabled and checking disabled (CD), allows remote attackers to conduct DNS cache poisoning attacks by receiving a recursive client query and sending a response that contains an Additional section with crafted data, which is not properly handled when the response is processed "at the same time as requesting DNSSEC records (DO)," aka Bug 20438.