An Unbound security update has been released for Ubuntu 18.04 LTS, 20.04 LTS. 22.04 LTS, and 22.10.

USN-5732-1: Unbound vulnerability

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Ubuntu Security Notice USN-5732-1
November 17, 2022

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

- Ubuntu 22.10
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Unbound could be made to stop responding if it received specially crafted
network traffic.

Software Description:
- unbound: validating, recursive, caching DNS resolver

Details:

It was discovered that Unbound incorrectly handled delegations with a large
number of non-responsive nameservers. A remote attacker could possibly use
this issue to cause Unbound to consume resources, leading to a denial of
service.

Update instructions:

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

Ubuntu 22.10:
libunbound8 1.16.2-1ubuntu0.1
unbound 1.16.2-1ubuntu0.1

Ubuntu 22.04 LTS:
libunbound8 1.13.1-1ubuntu5.3
unbound 1.13.1-1ubuntu5.3

Ubuntu 20.04 LTS:
libunbound8 1.9.4-2ubuntu1.4
unbound 1.9.4-2ubuntu1.4

Ubuntu 18.04 LTS:
libunbound2 1.6.7-1ubuntu2.6
unbound 1.6.7-1ubuntu2.6

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

References:
https://ubuntu.com/security/notices/USN-5732-1
CVE-2022-3204

Package Information:
https://launchpad.net/ubuntu/+source/unbound/1.16.2-1ubuntu0.1
https://launchpad.net/ubuntu/+source/unbound/1.13.1-1ubuntu5.3
https://launchpad.net/ubuntu/+source/unbound/1.9.4-2ubuntu1.4
https://launchpad.net/ubuntu/+source/unbound/1.6.7-1ubuntu2.6