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Fencer Vulns
medium 5.3

CVE-2026-4893 json

CVE-2026-4893

published 2026-05-11 5 mo ago modified 2026-06-17 4 mo 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

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 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
show 3 more
  • 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 OpenShift Container Platform 4.19 rhcos 4.19.9.6.202607151909
    fixed: vendor fix RHSA-2026:40762
  • 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
    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
5 mo ago

Exploit prediction

1.78% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 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.