A denial of service flaw was found in the way BIND processed certain records with malformed class attributes. A remote attacker could use this flaw to send a query to request a cached record with a malformed class attribute that would cause named functioning as an authoritative or recursive server to crash. Note: This issue affects authoritative servers as well as recursive servers, however authoritative servers are at limited risk if they perform authentication when making recursive queries to resolve addresses for servers listed in NS RRSETs.