Michael Sinatra discovered that the DNS resolver component in BIND does not properly check DNS records contained in additional sections of DNS responses, leading to a cache poisoning vulnerability. This vulnerability is only present in resolvers which have been configured with DNSSEC trust anchors, which is still rare. Note that this update contains an internal ABI change, which means that all BIND-related packages must be updated at the same time . In the unlikely event that you have compiled your own software against libdns, you must recompile this programs, too. For the old stable distribution , this problem has been fixed in version 9.3.4-2etch6. For the stable distribution , this problem has been fixed in version 9.5.1.dfsg.P3-1+lenny1. For the unstable distribution and the testing distribution , this problem has been fixed in version 9.6.1.dfsg.P2-1. We recommend that you upgrade your bind9 packages.