We have today posted updated versions of 9.9.6 and 9.10.1 to address a significant security vulnerability in DNS resolution. The flaw was discovered by Florian Maury of ANSSI, and applies to any recursive resolver that does not support a limit on the number of recursions. [CERTFR-2014-AVI-512, http://cert.ssi.gouv.fr/site/CERTFR-2014-AVI-512/index.html], [USCERT VU#264212 www.kb.cert.org/vuls/id/264212]
A flaw in delegation handling could be exploited to put named into an infinite loop, in which each lookup of a name server triggered additional lookups of more name servers. This has been addressed by placing limits on the number of levels of recursion named will allow (default 7), and on the number of queries that it will send before terminating a recursive query (default 50). The recursion depth limit is configured via the max-recursion-depth option, and the query limit via the max-recursion-queries option. For more information, see the security advisory at https://kb.isc.org/article/AA-01216/. [CVE-2014-8500] [RT #37580]
In addition, we have also corrected a potential security vulnerability in the GeoIP feature in the 9.10.1 release only. For more information on this issue, see the security advisory at https://kb.isc.org/article/AA-01217. [CVE-2014-8680]
Please review the release notes below.
Update as of December 15th, from ANSSI the French cert, on the vulnerability http://www.ssi.gouv.fr/en/the-anssi/events/vulnerabilty-disclosure-the-infinitely-delegating-name-servers-idns-attack.html