BIND was found to not properly handle certain configuration options, unintentionally permiting all clients to perform recursive queries. This occurs when "recursion yes;" is in effect and no match list values are provided for "allow-query-cache" or "allow-query" for the setting of "allow-recursion" to inherit a setting of all hosts from the "allow-query" setting default. https://nvd.nist.gov/vuln/detail/CVE-2018-5738
