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Fencer Intel
high 7.5

CVE-2026-6507 json

Dnsmasq: dnsmasq: denial of service due to out-of-bounds write in dhcp bootreply processing

published 6mo ago modified 6d ago also EUVD-2026-23419

cvss
7.5
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 42%
public exploits
0
none known

Summary

A flaw was found in dnsmasq. A remote attacker could exploit an out-of-bounds write vulnerability by sending a specially crafted BOOTREPLY (Bootstrap Protocol Reply) packet to a dnsmasq server configured with the `--dhcp-split-relay` option. This can lead to memory corruption, causing the dnsmasq daemon to crash and resulting in a denial of service (DoS).

Patch / fix

  • thekelleys.org.uk dnsmasq 2.93
  • dnsmasq Debian 14 2.92-4

debian advisories DEBIAN-CVE-2026-6507

  • dnsmasq Ubuntu 26.04 LTS 2.92-1ubuntu0.3

ubuntu advisories UBUNTU-CVE-2026-6507

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 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 2.92rel2-18.27.1

suse advisories SUSE-SU-2026:22454-1SUSE-SU-2026:22496-1SUSE-SU-2026:2458-1

  • dnsmasq openSUSE Leap 16.0 2.93-160000.1.1
  • dnsmasq openSUSE Tumbleweed 2.92-3.1

opensuse advisories openSUSE-SU-2026:21192-1openSUSE-SU-2026:10605-1

Is CVE-2026-6507 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2026-6507 updated cvss 7.5

dnsmasq: dnsmasq: Denial of Service due to out-of-bounds write in DHCP BOOTREPLY processing

  • Red Hat Enterprise Linux 6 dnsmasq, dnsmasq-utils Red Hat Enterprise Linux 7 dnsmasq, dnsmasq-utils
    not affected: vulnerable code not present
  • Red Hat Enterprise Linux 8 dnsmasq, dnsmasq-utils
    not affected: component not present
  • 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
    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
6mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • thekelleys.org.uk dnsmasq
  • 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

Classification

Weakness

References

Sources

Fencer Intel 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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.