==========================================================================
Ubuntu Security Notice USN-6665-1
February 28, 2024

unbound vulnerabilities
==========================================================================

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

- Ubuntu 23.10
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in Unbound.

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

Details:

Elias Heftrig, Haya Schulmann, Niklas Vogel, and Michael Waidner discovered
that Unbound incorrectly handled validating DNSSEC messages. A remote
attacker could possibly use this issue to cause Unbound to consume
resources, leading to a denial of service. (CVE-2023-50387)

It was discovered that Unbound incorrectly handled preparing an NSEC3
closest encloser proof. A remote attacker could possibly use this issue to
cause Unbound to consume resources, leading to a denial of service.
(CVE-2023-50868)

Update instructions:

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

Ubuntu 23.10:
   libunbound8                     1.17.1-2ubuntu0.1
   unbound                         1.17.1-2ubuntu0.1

Ubuntu 22.04 LTS:
   libunbound8                     1.13.1-1ubuntu5.4
   unbound                         1.13.1-1ubuntu5.4

Ubuntu 20.04 LTS:
   libunbound8                     1.9.4-2ubuntu1.5
   unbound                         1.9.4-2ubuntu1.5

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

References:
   https://ubuntu.com/security/notices/USN-6665-1
   CVE-2023-50387, CVE-2023-50868

Package Information:
   https://launchpad.net/ubuntu/+source/unbound/1.17.1-2ubuntu0.1
   https://launchpad.net/ubuntu/+source/unbound/1.13.1-1ubuntu5.4
   https://launchpad.net/ubuntu/+source/unbound/1.9.4-2ubuntu1.5