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Ubuntu Security Notice USN-6421-1
October 09, 2023
bind9 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.04 LTS (Available with Ubuntu Pro)
- Ubuntu 16.04 LTS (Available with Ubuntu Pro)
- Ubuntu 14.04 LTS (Available with Ubuntu Pro)
Summary:
Bind could be made to crash if it received specially crafted network 
traffic.
Software Description:
- bind9: Internet Domain Name Server
Details:
It was discovered that Bind incorrectly handled certain control channel
messages. A remote attacker with access to the control channel could
possibly use this issue to cause Bind to crash, resulting in a denial of
service.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 18.04 LTS (Available with Ubuntu Pro):
   bind9 1:9.11.3+dfsg-1ubuntu1.19+esm2
   libbind9-160                    1:9.11.3+dfsg-1ubuntu1.19+esm2
Ubuntu 16.04 LTS (Available with Ubuntu Pro):
   bind9 1:9.10.3.dfsg.P4-8ubuntu1.19+esm7
   libbind9-140  1:9.10.3.dfsg.P4-8ubuntu1.19+esm7
Ubuntu 14.04 LTS (Available with Ubuntu Pro):
   bind9 1:9.9.5.dfsg-3ubuntu0.19+esm11
   libbind9-90                     1:9.9.5.dfsg-3ubuntu0.19+esm11
In general, a standard system update will make all the necessary changes.
References:
   https://ubuntu.com/security/notices/USN-6421-1
   CVE-2023-3341