Debian 9 Stretch DLA-2647-1 Critical: Bind9 Denial of Service Fix

CVE-2021-25214

Greg Kuechle discovered that a malformed incoming IXFR transfer
could trigger an assertion failure in named, resulting in denial
of service.

CVE-2021-25215

Siva Kakarla discovered that named could crash when a DNAME record
placed in the ANSWER section during DNAME chasing turned out to be
the final answer to a client query.

CVE-2021-25216

It was discovered that the SPNEGO implementation used by BIND is
prone to a buffer overflow vulnerability. This update switches to
use the SPNEGO implementation from the Kerberos libraries.

For Debian 9 stretch, these problems have been fixed in version
1:9.10.3.dfsg.P4-12.3+deb9u9.

We recommend that you upgrade your bind9 packages.

For the detailed security status of bind9 please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/bind9

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be