Debian 11 Bind9 Important DNSSEC CPU Consumption Threat DLA-4529-1

If a BIND resolver is performing DNSSEC validation and encounters
a maliciously crafted zone, the resolver may consume excessive CPU.

Authoritative-only servers are generally unaffected,
although there are circumstances where authoritative servers
may make recursive queries

For Debian 11 bullseye, this problem has been fixed in version
1:9.16.50-1~deb11u5.

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/bind9

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS