[USN-7759-1] Kea DHCP vulnerabilities

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Ubuntu Security Notice USN-7759-1
September 21, 2025

isc-kea vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Kea DHCP could be made to crash if it received specially crafted network
traffic.

Software Description:
- isc-kea: Standards-based DHCP server

Details:

It was discovered that Kea DHCP did not correctly handle invalid hostnames.
A remote attacker could possibly use this issue to cause a denial of
service.

Update instructions:

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

Ubuntu 18.04 LTS
kea-admin 1.1.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
kea-common 1.1.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
kea-dhcp-ddns-server 1.1.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
kea-dhcp4-server 1.1.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
kea-dhcp6-server 1.1.0-1ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 16.04 LTS
kea-admin 1.0.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
kea-common 1.0.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
kea-dhcp-ddns-server 1.0.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
kea-dhcp4-server 1.0.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
kea-dhcp6-server 1.0.0-1ubuntu0.1~esm1
Available with Ubuntu Pro

After a standard system update you may need to restart Kea DHCP server
instances to make all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-7759-1
CVE-2019-6473