[USN-8542-1] Dnsmasq vulnerabilities

[noreply+usn-bot at canonical.com]

==========================================================================
Ubuntu Security Notice USN-8542-1
July 14, 2026

dnsmasq vulnerabilities
==========================================================================

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

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

Summary:

Several security issues were fixed in Dnsmasq.

Software Description:
- dnsmasq: Small caching DNS proxy and DHCP/TFTP server

Details:

Yiwei Hou discovered that Dnsmasq incorrectly handled logging of DS or
DNSKEY. A remote attacker could possibly use this issue to cause a
denial of service. (CVE-2026-12725)

It was discovered that Dnsmasq incorrectly validated the length of
fixed-length DNS record fields when parsing NS section records. A remote
attacker could possibly use this issue to cause Dnsmasq to read out of
bounds, possibly exposing sensitive information. (CVE-2026-12969)

Update instructions:

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

Ubuntu 26.04 LTS
  dnsmasq                         2.92-1ubuntu0.4
  dnsmasq-base                    2.92-1ubuntu0.4
  dnsmasq-base-lua                2.92-1ubuntu0.4
  dnsmasq-utils                   2.92-1ubuntu0.4

Ubuntu 24.04 LTS
  dnsmasq                         2.90-2ubuntu0.4
  dnsmasq-base                    2.90-2ubuntu0.4
  dnsmasq-base-lua                2.90-2ubuntu0.4
  dnsmasq-utils                   2.90-2ubuntu0.4

Ubuntu 22.04 LTS
  dnsmasq                         2.90-0ubuntu0.22.04.4
  dnsmasq-base                    2.90-0ubuntu0.22.04.4
  dnsmasq-base-lua                2.90-0ubuntu0.22.04.4
  dnsmasq-utils                   2.90-0ubuntu0.22.04.4

Ubuntu 20.04 LTS
  dnsmasq                         2.90-0ubuntu0.20.04.1+esm3
                                  Available with Ubuntu Pro
  dnsmasq-base                    2.90-0ubuntu0.20.04.1+esm3
                                  Available with Ubuntu Pro
  dnsmasq-base-lua                2.90-0ubuntu0.20.04.1+esm3
                                  Available with Ubuntu Pro
  dnsmasq-utils                   2.90-0ubuntu0.20.04.1+esm3
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  dnsmasq                         2.90-0ubuntu0.18.04.1+esm4
                                  Available with Ubuntu Pro
  dnsmasq-base                    2.90-0ubuntu0.18.04.1+esm4
                                  Available with Ubuntu Pro
  dnsmasq-base-lua                2.90-0ubuntu0.18.04.1+esm4
                                  Available with Ubuntu Pro
  dnsmasq-utils                   2.90-0ubuntu0.18.04.1+esm4
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  dnsmasq                         2.90-0ubuntu0.16.04.1+esm4
                                  Available with Ubuntu Pro
  dnsmasq-base                    2.90-0ubuntu0.16.04.1+esm4
                                  Available with Ubuntu Pro
  dnsmasq-base-lua                2.90-0ubuntu0.16.04.1+esm4
                                  Available with Ubuntu Pro
  dnsmasq-utils                   2.90-0ubuntu0.16.04.1+esm4
                                  Available with Ubuntu Pro

After a standard system update you need to restart dnsmasq to make
all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-8542-1
  CVE-2026-12725, CVE-2026-12969

Package Information:
  https://launchpad.net/ubuntu/+source/dnsmasq/2.92-1ubuntu0.4
  https://launchpad.net/ubuntu/+source/dnsmasq/2.90-2ubuntu0.4
  https://launchpad.net/ubuntu/+source/dnsmasq/2.90-0ubuntu0.22.04.4
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