CVE-2026-4890: A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a

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HIGH 7.5REMOTE

CVE-2026-4890 is a high-severity flaw (CVSS 7.5) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.

Why this priority

High severity
EPSS top 5%: very likely to be exploited
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	8.8% (top 5%)
CISA exploited list	No
Weakness	CWE-835
Published	2026-05-11
Last modified	2026-08-25

Publisher (CNA): CERT/CC

Last updated 2026-08-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-05-11 18:16 UTCPublished CVE record published
2026-08-25 13:19 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · fzssh · FIXED · 1.4.0-2.fc46 · FEDORA-2026-8004fcd067 · source

sudo dnf upgrade --advisory=FEDORA-2026-8004fcd067

Ubuntu 24.04 · dnsmasq · FIXED · 2.90-2ubuntu0.3

sudo apt update && sudo apt install --only-upgrade dnsmasq dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dnsmasq)" ge "2.90-2ubuntu0.3" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 20.04 · dnsmasq · FIXED · 2.90-0ubuntu0.20.04.1+esm2

sudo apt update && sudo apt install --only-upgrade dnsmasq dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dnsmasq)" ge "2.90-0ubuntu0.20.04.1+esm2" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · dnsmasq · FIXED · 2.90-0ubuntu0.22.04.3

sudo apt update && sudo apt install --only-upgrade dnsmasq dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dnsmasq)" ge "2.90-0ubuntu0.22.04.3" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 25.10 · dnsmasq · FIXED · 2.91-1ubuntu0.2

sudo apt update && sudo apt install --only-upgrade dnsmasq dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dnsmasq)" ge "2.91-1ubuntu0.2" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · dnsmasq · FIXED · 2.90-4~deb12u2

sudo apt update && sudo apt install --only-upgrade dnsmasq dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dnsmasq)" ge "2.90-4~deb12u2" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · dnsmasq · FIXED · 2.91-1+deb13u1

sudo apt update && sudo apt install --only-upgrade dnsmasq dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dnsmasq)" ge "2.91-1+deb13u1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · dnsmasq · FIXED · dnsmasq-2.90-7.el10_2

sudo dnf upgrade --advisory=RHSA-2026:19158 rpm -q dnsmasq

RHEL 8 · dnsmasq · FIXED · dnsmasq-2.79-36.el8_10

sudo dnf upgrade --advisory=RHSA-2026:20589 rpm -q dnsmasq

RHEL 9 · dnsmasq · FIXED · dnsmasq-2.85-18.el9_8.1

sudo dnf upgrade --advisory=RHSA-2026:19373 rpm -q dnsmasq

RHEL 9.6 Extended Update Support · dnsmasq · FIXED · dnsmasq-2.85-17.el9_6.1

sudo dnf upgrade --advisory=RHSA-2026:34508 rpm -q dnsmasq

RHEL 6 · dnsmasq · DEFERRED

Alpine 3.22 · dnsmasq · FIXED · dnsmasq-2.91-r1

apk add --upgrade dnsmasq apk info -v dnsmasq

Alpine 3.23 · dnsmasq · FIXED · dnsmasq-2.91-r1

apk add --upgrade dnsmasq apk info -v dnsmasq

Alpine 3.24 · dnsmasq · FIXED · dnsmasq-2.92_p2-r0

apk add --upgrade dnsmasq apk info -v dnsmasq

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-1729 · source

sudo dnf update --advisory=ALAS2023-2026-1729

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-4890?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-4890 being exploited?

CVE-2026-4890 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-4890 affect?

CVE-2026-4890 affects affected software. Severity is high (CVSS 7.5). A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.

How urgent is CVE-2026-4890?

Priority 55/100. High severity; EPSS top 5%: very likely to be exploited; Remotely exploitable, no login, no user action

Software pages

Dnsmasq vulnerabilities

References

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