From the upstream report [1]:

This advisory only affects BIND users who are using the RPZ feature configured for RRset replacement. BIND 9.8.0 introduced Response Policy Zones (RPZ), a mechanism for modifying DNS responses returned by a recursive server according to a set of rules which are either defined locally or imported from a reputation provider. In typical configurations, RPZ is used to force NXDOMAIN responses for untrusted names. It can also be used for RRset replacement, i.e., returning a positive answer defined by the response policy. When RPZ is being used, a query of type RRSIG for a name configured for RRset replacement will trigger an assertion failure and cause the name server process to exit.

[1] http://www.isc.org/CVE-2011-1907


Statement:

Not vulnerable. This issue did not affect the versions of bind as shipped with Red Hat Enterprise Linux 4, 5, or 6 as they did not include support for Response Policy Zones (RPZ).