ISC BIND 9.0.x through 9.3.x, 9.4 before 9.4.3-P5, 9.5 before 9.5.2-P2, 9.6 before 9.6.1-P3, and 9.7.0 beta does not properly validate DNSSEC (1) NSEC and (2) NSEC3 records, which allows remote attackers to add the Authenticated Data (AD) flag to a forged NXDOMAIN response for an existing domain.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.