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Fencer Vulns
medium 5.3

CVE-2026-12969 json

Dnsmasq: dnsmasq: out-of-bounds read in find_soa() due to missing extrabytes validation

published 2026-06-23 4 mo ago modified 2026-11-06 2 d ago also EUVD-2026-38449

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

An out-of-bounds read vulnerability exists in dnsmasq's find_soa() function in src/rfc1035.c. When parsing NS section records, extract_name() is called with extrabytes=0, failing to validate that 10 additional bytes exist for fixed-length DNS record fields. A remote attacker controlling a DNS zone can exploit this via a crafted NXDOMAIN response to cause a 10-byte heap out-of-bounds read, potentially accessing stale data from prior transactions.

Patch / fix

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

debian advisories DEBIAN-CVE-2026-12969

  • 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-2026-12969

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_2.1
  • 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-2026:22668-1

  • dnsmasq openSUSE Tumbleweed 2.93-2.1

opensuse advisories openSUSE-SU-2026:11172-1

  • dnsmasq Azure Linux 3.0 2.93-1

azure linux advisories AZL-91164

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-2026-12969 updated cvss 5.3

dnsmasq: dnsmasq: out-of-bounds read in find_soa() due to missing extrabytes validation

  • Red Hat Enterprise Linux 10 dnsmasq
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 dnsmasq, dnsmasq-utils Red Hat Enterprise Linux 7 dnsmasq, dnsmasq-utils Red Hat Enterprise Linux 8 dnsmasq, dnsmasq-utils Red Hat Enterprise Linux 9 dnsmasq, dnsmasq-utils 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
    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
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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

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.