Off-by-one error in named in ISC BIND 9.x before 9.7.3-P1, 9.8.x before 9.8.0-P2, 9.4-ESV before 9.4-ESV-R4-P1, and 9.6-ESV before 9.6-ESV-R4-P1 allows remote DNS servers to cause a denial of service (assertion failure and daemon exit) via a negative response containing large RRSIG RRsets.