A Bind security update has been released for Ubuntu Linux 16.04 LTS, 18.04 LTS, 20.04 LTS, and 20.10 to address an incorrectly handled GSSAPI security policy negotiation.

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Ubuntu Security Notice USN-4737-1
February 18, 2021

bind9 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Bind could be made to crash or run programs if it received specially
crafted network traffic.

Software Description:
- bind9: Internet Domain Name Server

Details:

It was discovered that Bind incorrectly handled GSSAPI security policy
negotiation. A remote attacker could use this issue to cause Bind to crash,
resulting in a denial of service, or possibly execute arbitrary code. In
the default installation, attackers would be isolated by the Bind AppArmor
profile.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.10:
bind9 1:9.16.6-3ubuntu1.1

Ubuntu 20.04 LTS:
bind9 1:9.16.1-0ubuntu2.6

Ubuntu 18.04 LTS:
bind9 1:9.11.3+dfsg-1ubuntu1.14

Ubuntu 16.04 LTS:
bind9 1:9.10.3.dfsg.P4-8ubuntu1.18

In general, a standard system update will make all the necessary changes.

References:
  https://usn.ubuntu.com/4737-1
CVE-2020-8625

Package Information:
  https://launchpad.net/ubuntu/+source/bind9/1:9.16.6-3ubuntu1.1
  https://launchpad.net/ubuntu/+source/bind9/1:9.16.1-0ubuntu2.6
  https://launchpad.net/ubuntu/+source/bind9/1:9.11.3+dfsg-1ubuntu1.14
  https://launchpad.net/ubuntu/+source/bind9/1:9.10.3.dfsg.P4-8ubuntu1.18