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Fencer Intel
medium 5.3

CVE-2026-4893 json

CVE-2026-4893

published 6mo ago modified 4mo ago also EUVD-2026-29155

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

An information disclosure vulnerability in dnsmasq allows remote attackers to bypass source checks via a crafted DNS packet with RFC 7871 client subnet information.

Patch / fix

  • dnsmasq dnsmasq 2.92rel2
  • dnsmasq Debian 12 2.90-4~deb12u2
  • dnsmasq Debian 13 2.91-1+deb13u1
  • dnsmasq Debian 14 2.92-5

debian advisories DEBIAN-CVE-2026-4893

  • dnsmasq Ubuntu 22.04 LTS 2.90-0ubuntu0.22.04.3
  • dnsmasq Ubuntu 24.04 LTS 2.90-2ubuntu0.3
  • dnsmasq Ubuntu 25.10 2.91-1ubuntu0.2
  • dnsmasq Ubuntu 26.04 LTS 2.92-1ubuntu0.2
  • dnsmasq Ubuntu Pro 14.04 LTS 2.68-1ubuntu0.2+esm5
  • dnsmasq Ubuntu Pro 16.04 LTS 2.90-0ubuntu0.16.04.1+esm3
  • dnsmasq Ubuntu Pro 18.04 LTS 2.90-0ubuntu0.18.04.1+esm3
  • dnsmasq Ubuntu Pro 20.04 LTS 2.90-0ubuntu0.20.04.1+esm2

ubuntu advisories UBUNTU-CVE-2026-4893

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 RHEL 8 2.79-36.el8_10
  • dnsmasq-utils RHEL 8 2.79-36.el8_10
  • dnsmasq RHEL 9 2.85-18.el9_8.1
  • dnsmasq-utils RHEL 9 2.85-18.el9_8.1
  • dnsmasq RHEL 10.2 2.90-7.el10_2
  • dnsmasq-utils RHEL 10.2 2.90-7.el10_2
  • dnsmasq RHEL 9.6 EUS 2.85-17.el9_6.1
  • dnsmasq-utils RHEL 9.6 EUS 2.85-17.el9_6.1

red hat advisories RHSA-2026:34508RHSA-2026:20589RHSA-2026:19373RHSA-2026:19158

  • dnsmasq SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.92rel2-18.27.1

suse advisories SUSE-SU-2026:2458-1

  • dnsmasq openSUSE Tumbleweed 2.92rel2-1.1

opensuse advisories openSUSE-SU-2026:10821-1

  • dnsmasq AlmaLinux 8 2.79-36.el8_10
  • dnsmasq-utils AlmaLinux 8 2.79-36.el8_10
  • dnsmasq AlmaLinux 10 2.90-7.el10_2
  • dnsmasq-utils AlmaLinux 10 2.90-7.el10_2
  • dnsmasq AlmaLinux 9 2.85-18.el9_8.1
  • dnsmasq-utils AlmaLinux 9 2.85-18.el9_8.1

almalinux advisories ALSA-2026:20589ALSA-2026:19158ALSA-2026:19373

  • dnsmasq Rocky Linux 10 2.90-7.el10_2
  • dnsmasq Rocky Linux 8 2.79-36.el8_10
  • dnsmasq Rocky Linux 9 2.85-18.el9_8.1

rocky linux advisories RLSA-2026:19158RLSA-2026:20589RLSA-2026:19373

  • dnsmasq Alpine 3.23, Alpine 3.22 2.91-r1
  • dnsmasq Alpine 3.24 2.92_p2-r0

alpine advisories ALPINE-CVE-2026-4893

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • dnsmasq Azure Linux 3.0 2.92-1

azure linux advisories AZL-86760

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

Is CVE-2026-4893 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.

Check with Fencer

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-2026-4893 updated cvss 6.5

dnsmasq: Broken ECS source validation bypass

  • Red Hat Enterprise Linux 6 dnsmasq, dnsmasq-utils
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 7 dnsmasq, dnsmasq-utils Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) dnsmasq 2.79-36.el8_10, dnsmasq-utils 2.79-36.el8_10
    fixed: vendor fix RHSA-2026:20589
  • Red Hat Enterprise Linux AppStream (v. 9) dnsmasq 2.85-18.el9_8.1, dnsmasq-utils 2.85-18.el9_8.1
    fixed: vendor fix RHSA-2026:19373
  • Red Hat Enterprise Linux AppStream (v. 10) dnsmasq 2.90-7.el10_2, dnsmasq-utils 2.90-7.el10_2
    fixed: vendor fix RHSA-2026:19158
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) dnsmasq 2.79-15.el8_4.3
    fixed: vendor fix RHSA-2026:98116
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) dnsmasq 2.79-21.el8_6.6
    fixed: vendor fix RHSA-2026:96241
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) dnsmasq 2.79-26.el8_8.5
    fixed: vendor fix RHSA-2026:96246
show 9 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) dnsmasq 2.85-6.el9_2.5
    fixed: vendor fix RHSA-2026:95093
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) dnsmasq 2.85-16.el9_4.1
    fixed: vendor fix RHSA-2026:95088
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) dnsmasq 2.90-4.el10_0.1
    fixed: vendor fix RHSA-2026:92677
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) dnsmasq 2.85-17.el9_6.1, dnsmasq-utils 2.85-17.el9_6.1
    fixed: vendor fix RHSA-2026:34508
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) dnsmasq 2.79-15.el8_4.3
    fixed: vendor fix RHSA-2026:98116
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) dnsmasq 2.79-21.el8_6.6
    fixed: vendor fix RHSA-2026:96241
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) dnsmasq 2.79-26.el8_8.5
    fixed: vendor fix RHSA-2026:96246
  • Red Hat OpenShift Container Platform 4.19 rhcos 4.19.9.6.202607151909
    fixed: vendor fix RHSA-2026:40762
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) dnsmasq-utils 2.79-15.el8_4.3 Red Hat Enterprise Linux AppStream AUS (v.8.6) dnsmasq-utils 2.79-21.el8_6.6 Red Hat Enterprise Linux AppStream E4S (v.8.8) dnsmasq-utils 2.79-26.el8_8.5 Red Hat Enterprise Linux AppStream E4S (v.9.2) dnsmasq-utils 2.85-6.el9_2.5 Red Hat Enterprise Linux AppStream E4S (v.9.4) dnsmasq-utils 2.85-16.el9_4.1 Red Hat Enterprise Linux AppStream EUS (v. 10.0) dnsmasq-utils 2.90-4.el10_0.1
    +3 more products
    Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) dnsmasq-utils 2.79-15.el8_4.3 Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) dnsmasq-utils 2.79-21.el8_6.6 Red Hat Enterprise Linux AppStream TUS (v.8.8) dnsmasq-utils 2.79-26.el8_8.5
    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

1.78% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

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

  • dnsmasq dnsmasq

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.