bind9 - wrong boundary condition

It was discovered that BIND, an implementation of the DNS protocol,
does not correctly process certain large RRSIG record sets in DNSSEC
responses. The resulting assertion failure causes the name server
process to crash, making name resolution unavailable. (CVE-2011-1910)

In addition, this update fixes handling of certain signed/unsigned
zone combinations when a DLV service is used. Previously, data from
certain affected zones could become unavailable from the resolver.

For the oldstable distribution (lenny), this problem has been fixed in
version 1:9.6.ESV.R4+dfsg-0+lenny2.

For the stable distribution (squeeze), this problem has been fixed in
version 1:9.7.3.dfsg-1~squeeze2.

The testing distribution (wheezy) and the unstable distribution (sid)
will be fixed soon.

We recommend that you upgrade your bind9 packages.