==========================================================================
Ubuntu Security Notice USN-8269-1
May 12, 2026

avahi vulnerabilities
==========================================================================

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

- Ubuntu 26.04 LTS
- Ubuntu 25.10
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in Avahi.

Software Description:
- avahi: IPv4LL network address configuration daemon

Details:

It is discovered that Avahi incorrectly handled crafted input. A
remote attacker could possibly use this issue to crash the program,
resulting in a denial of service. This issue only affected Ubuntu
14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS,
Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. (CVE-2026-24401)

Guillaume Meunier discovered that Avahi incorrectly handled crafted
input. An attacker could possibly use this issue to crash the
program, resulting in a denial of service. (CVE-2026-34933)

Update instructions:

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

Ubuntu 26.04 LTS
  avahi-daemon                    0.8-18ubuntu1.1

Ubuntu 25.10
  avahi-daemon                    0.8-16ubuntu3.2

Ubuntu 24.04 LTS
  avahi-daemon                    0.8-13ubuntu6.2

Ubuntu 22.04 LTS
  avahi-daemon                    0.8-5ubuntu5.5

Ubuntu 20.04 LTS
  avahi-daemon                    0.7-4ubuntu7.3+esm2
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  avahi-daemon                    0.7-3.1ubuntu1.3+esm4
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  avahi-daemon                    0.6.32~rc+dfsg-1ubuntu2.3+esm5
                                  Available with Ubuntu Pro

Ubuntu 14.04 LTS
  avahi-daemon                    0.6.31-4ubuntu1.3+esm5
                                  Available with Ubuntu Pro



References:
  https://ubuntu.com/security/notices/USN-8269-1
  CVE-2026-24401, CVE-2026-34933

Package Information:
  https://launchpad.net/ubuntu/+source/avahi/0.8-18ubuntu1.1
  https://launchpad.net/ubuntu/+source/avahi/0.8-16ubuntu3.2
  https://launchpad.net/ubuntu/+source/avahi/0.8-13ubuntu6.2
  https://launchpad.net/ubuntu/+source/avahi/0.8-5ubuntu5.5