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Fencer Intel
medium 6.5

CVE-2026-24401 json

Avahi has Uncontrolled Recursion in lookup_handle_cname function

published 9mo ago modified 17d ago also EUVD-2026-4603

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In versions 0.9rc2 and below, avahi-daemon can be crashed via a segmentation fault by sending an unsolicited mDNS response containing a recursive CNAME record, where the alias and canonical name point to the same domain (e.g., "h.local" as a CNAME for "h.local"). This causes unbounded recursion in the lookup_handle_cname function, leading to stack exhaustion. The vulnerability affects record browsers where AVAHI_LOOKUP_USE_MULTICAST is set explicitly, which includes record browsers created by resolvers used by nss-mdns. This issue is patched in commit 78eab31128479f06e30beb8c1cbf99dd921e2524, which is part of version 0.9-rc3.

Patch / fix

  • avahi avahi 0.9
  • avahi Debian 14 0.8-18

debian advisories DEBIAN-CVE-2026-24401

  • avahi Ubuntu 22.04 LTS 0.8-5ubuntu5.5
  • avahi Ubuntu 24.04 LTS 0.8-13ubuntu6.2
  • avahi Ubuntu 25.10 0.8-16ubuntu3.2
  • avahi Ubuntu Pro 14.04 LTS 0.6.31-4ubuntu1.3+esm5
  • avahi Ubuntu Pro 16.04 LTS 0.6.32~rc+dfsg-1ubuntu2.3+esm5
  • avahi Ubuntu Pro 18.04 LTS 0.7-3.1ubuntu1.3+esm4
  • avahi Ubuntu Pro 20.04 LTS 0.7-4ubuntu7.3+esm2

ubuntu advisories UBUNTU-CVE-2026-24401

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

  • avahi hummingbird 1 0.9~rc4-0.1.hum1
  • avahi-ui hummingbird 1 0.9~rc4-0.1.hum1
  • avahi-qt3 hummingbird 1 0.9~rc4-0.1.hum1
  • avahi-qt4 hummingbird 1 0.9~rc4-0.1.hum1
  • avahi-qt5 hummingbird 1 0.9~rc4-0.1.hum1
  • avahi-glib hummingbird 1 0.9~rc4-0.1.hum1
  • avahi-libs hummingbird 1 0.9~rc4-0.1.hum1
  • avahi-sharp hummingbird 1 0.9~rc4-0.1.hum1

red hat advisories RHSA-2026:11316

  • avahi SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 0.8-160000.5.1
  • avahi-glib2 SLES for SAP applications 16.0, SLES 16.0 0.8-160000.5.1
  • avahi SLE Micro 5.5, SLE Micro 5.4, SLE Micro 5.3 0.8-150400.7.31.2
  • avahi SLE Module for Package Hub 15 SP7, SLE Module for Desktop Applications 15 SP7, SLE Module for Basesystem 15 SP7 +1 more 0.8-150600.15.15.1
  • avahi-qt5 openSUSE Leap 15.6 0.8-150600.15.15.1
  • avahi-glib2 SLE Module for Desktop Applications 15 SP7, SLE Module for Basesystem 15 SP7, openSUSE Leap 15.6 0.8-150600.15.15.1
  • avahi Linux Micro 6.1 0.8-slfo.1.1_5.1
  • avahi Linux Micro 6.0 0.8-8.1

suse advisories SUSE-SU-2026:22258-1SUSE-SU-2026:22338-1SUSE-SU-2026:2311-1SUSE-SU-2026:1442-1SUSE-SU-2026:1441-1SUSE-SU-2026:21117-1

  • avahi openSUSE Leap 16.0 0.8-160000.5.1
  • avahi-qt6 openSUSE Leap 16.0 0.8-160000.5.1
  • avahi-glib2 openSUSE Leap 16.0 0.8-160000.5.1
  • avahi openSUSE Tumbleweed 0.8-44.1

opensuse advisories openSUSE-SU-2026:21014-1openSUSE-SU-2026:10701-1

  • avahi Alpine 3.24 0.8-r25

alpine advisories ALPINE-CVE-2026-24401

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

  • avahi CBL-Mariner 2.0 0.8-5
  • avahi Azure Linux 3.0 0.8-7

azure linux advisories AZL-75204AZL-75207

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-2026-24401 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-2026-24401 updated cvss 6.5

avahi: Avahi: Denial of Service via recursive CNAME record in mDNS response

  • Red Hat Enterprise Linux 6 avahi, avahi-ui, avahi-qt3, avahi-qt4, avahi-glib, avahi-libs, +7 more Red Hat Enterprise Linux 7 avahi, avahi-ui, avahi-qt3, avahi-qt4, avahi-glib, avahi-libs, +8 more Red Hat Enterprise Linux 8 avahi, avahi-ui, avahi-glib, avahi-libs, avahi-tools, avahi-autoipd, +5 more Red Hat Enterprise Linux 9 avahi, avahi-glib, avahi-libs, avahi-tools, avahi-autoipd, avahi-gobject, +2 more Red Hat Enterprise Linux 10 avahi Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images avahi 0.9~rc4-0.1.hum1, avahi-ui 0.9~rc4-0.1.hum1, avahi-qt3 0.9~rc4-0.1.hum1, avahi-qt4 0.9~rc4-0.1.hum1, avahi-qt5 0.9~rc4-0.1.hum1, avahi-glib 0.9~rc4-0.1.hum1, +11 more
    fixed: vendor fix RHSA-2026:11316

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
no
Technical impact
partial
Assessed
9mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected products

  • avahi avahi

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.