BIND was improperly sequencing cleanup operations on upstream recursion fetch contexts leading in some cases to a use-after-free error that can trigger an assertion failure and crash in named. Affects BIND 9.0.0 to 9.8.x 9.9.0 to 9.9.11 9.10.0 to 9.10.6 9.11.0 to 9.11.2 9.9.3-S1 to 9.9.11-S1 9.10.5-S1 to 9.10.6-S1 9.12.0a1 to 9.12.0rc1.