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Fencer Vulns
medium 5.9

CVE-2026-12725 json

Dnsmasq: dnsmasq: heap buffer overflow in log_query() when logging unsupported ds/dnskey replies

published 2026-06-22 4 mo ago modified 2026-11-05 4 d ago also EUVD-2026-38278

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and query logging are both enabled, logging of DS or DNSKEY replies containing unsupported algorithm or digest types can cause dnsmasq to write past the end of an internal logging buffer. A remote attacker able to supply such a DNS response may crash the dnsmasq process, resulting in denial of service.

Patch / fix

  • thekelleys dnsmasq 2.93
  • dnsmasq Debian 13 2.91-1+deb13u2
  • dnsmasq Debian 14 2.93-1

debian advisories DEBIAN-CVE-2026-12725

  • dnsmasq Ubuntu 22.04 LTS 2.90-0ubuntu0.22.04.4
  • dnsmasq Ubuntu 24.04 LTS 2.90-2ubuntu0.4
  • dnsmasq Ubuntu 26.04 LTS 2.92-1ubuntu0.4
  • dnsmasq Ubuntu Pro 16.04 LTS 2.90-0ubuntu0.16.04.1+esm4
  • dnsmasq Ubuntu Pro 18.04 LTS 2.90-0ubuntu0.18.04.1+esm4
  • dnsmasq Ubuntu Pro 20.04 LTS 2.90-0ubuntu0.20.04.1+esm3

ubuntu advisories UBUNTU-CVE-2026-12725

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • dnsmasq SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +11 more 2.93-150400.16.17.1
  • dnsmasq Linux Micro 6.0 2.93-1.1
  • dnsmasq Linux Micro 6.1 2.93-slfo.1.1_1.1
  • dnsmasq SLES for SAP applications 16.0, SLES 16.0 2.93-160000.1.1
  • dnsmasq SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.93-18.32.1

suse advisories SUSE-SU-2026:3028-1SUSE-SU-2026:2974-1SUSE-SU-2026:22706-1SUSE-SU-2026:22454-1SUSE-SU-2026:22496-1

  • dnsmasq openSUSE Leap 16.0 2.93-160000.1.1
  • dnsmasq openSUSE Tumbleweed 2.93-1.1

opensuse advisories openSUSE-SU-2026:21192-1openSUSE-SU-2026:11116-1

  • dnsmasq Azure Linux 3.0 2.93-1

azure linux advisories AZL-91167

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-12725 updated cvss 5.9

dnsmasq: dnsmasq: heap buffer overflow in log_query() when logging unsupported DS/DNSKEY replies

  • Red Hat Enterprise Linux 8 dnsmasq, dnsmasq-utils Red Hat Enterprise Linux 9 dnsmasq, dnsmasq-utils Red Hat Enterprise Linux 10 dnsmasq Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 dnsmasq, dnsmasq-utils Red Hat Enterprise Linux 7 dnsmasq, dnsmasq-utils
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat OpenShift Container Platform 4
  • Red Hat Red Hat OpenShift Container Platform 5

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.