Skip to content
Fencer Intel
medium 5.3

CVE-2026-80225 json

Possible degradation of service from continuous queries on the same TCP/DoT connection

published last mo. modified last mo. also EUVD-2026-80289

cvss
5.3
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

In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.

Patch / fix

  • NLnet Labs Unbound 1.26.1
  • unbound Debian 13 1.26.1-0+deb13u1
  • unbound Debian 14 1.26.1-1

debian advisories DEBIAN-CVE-2026-80225

  • unbound Ubuntu 22.04 LTS 1.13.1-1ubuntu5.17
  • unbound Ubuntu 24.04 LTS 1.19.2-1ubuntu3.12
  • unbound Ubuntu 26.04 LTS 1.24.2-1ubuntu2.4
  • unbound Ubuntu Pro 20.04 LTS 1.9.4-2ubuntu1.11+esm3

ubuntu advisories UBUNTU-CVE-2026-80225

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

  • unbound hummingbird 1 1.26.1-1.hum1
  • unbound-libs hummingbird 1 1.26.1-1.hum1
  • unbound-munin hummingbird 1 1.26.1-1.hum1
  • unbound-utils hummingbird 1 1.26.1-1.hum1
  • unbound-anchor hummingbird 1 1.26.1-1.hum1
  • unbound-dracut hummingbird 1 1.26.1-1.hum1
  • python3-unbound hummingbird 1 1.26.1-1.hum1

red hat advisories RHSA-2026:68590

  • unbound Linux Micro 6.1 1.26.1-slfo.1.1_1.1
  • unbound SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +6 more 1.26.1-150100.10.31.1
  • unbound SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Package Hub 15 SP7 +1 more 1.26.1-150600.23.24.1
  • unbound SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 1.26.1-160000.1.1
  • unbound Linux Micro 6.0 1.26.1-159998.1.1

suse advisories SUSE-SU-2026:24376-1SUSE-SU-2026:4624-1SUSE-SU-2026:4620-1SUSE-SU-2026:24128-1SUSE-SU-2026:24226-1SUSE-SU-2026:24135-1

  • unbound openSUSE Leap 16.0 1.26.1-160000.1.1
  • unbound openSUSE Tumbleweed 1.26.1-1.1

opensuse advisories openSUSE-SU-2026:22082-1openSUSE-SU-2026:11930-1

  • unbound Azure Linux 3.0 1.26.1-1

azure linux advisories AZL-101724

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-2026-80225 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-2026-80225 updated cvss 5.3

unbound: Unbound: Denial of Service via continuous queries on TCP/DoT connection

  • Red Hat Enterprise Linux 6 unbound, unbound-libs, unbound-python
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 unbound, unbound-libs, unbound-python Red Hat Enterprise Linux 8 unbound, unbound-libs, python3-unbound Red Hat Enterprise Linux 9 unbound, unbound-libs, unbound-dracut, python3-unbound Red Hat Enterprise Linux 10 unbound 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
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images unbound 1.26.1-1.hum1, unbound-libs 1.26.1-1.hum1, unbound-munin 1.26.1-1.hum1, unbound-utils 1.26.1-1.hum1, unbound-anchor 1.26.1-1.hum1, unbound-dracut 1.26.1-1.hum1, +1 more
    fixed: vendor fix RHSA-2026:68590

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
last mo.

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 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 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

  • NLnet Labs Unbound

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

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.