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CVE-2026-34933· NVD / CVE Program· CNA GitHub_M

Avahi: Reachable assertion in `transport_flags_from_domain()` via conflicting publish flags crashes avahi-daemon

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. Prior to version 0.9-rc4, any unprivileged local user can crash avahi-daemon by sending a single D-Bus method call with conflicting publish flags. This issue has been patched in version 0.9-rc4.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Apr 3, 2026
Updated
Jul 24, 2026
EPSS
0.2% · 5th percentile
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Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
5.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
avahiavahi

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • avahi avahibefore 0.9
  • avahi avahi0.9

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • avahi avahi

    • < 0.9-rc4affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.24avahibefore 0.8-r260.8-r26
Debian:12avahiall versions—
openSUSE:Leap 16.0avahibefore 0.8-160000.5.10.8-160000.5.1
openSUSE:Leap 16.0avahi-glib2before 0.8-160000.5.10.8-160000.5.1
openSUSE:Leap 16.0avahi-qt6before 0.8-160000.5.10.8-160000.5.1
openSUSE:Tumbleweedavahibefore 0.8-43.10.8-43.1
Red Hat:hummingbird:1avahibefore 0:0.9~rc4-0.1.hum10:0.9~rc4-0.1.hum1
SUSE:Linux Enterprise Micro 5.3avahibefore 0.8-150400.7.31.20.8-150400.7.31.2
SUSE:Linux Enterprise Server 16.0avahi-glib2before 0.8-160000.5.10.8-160000.5.1
SUSE:Linux Micro 6.2avahibefore 0.8-160000.5.10.8-160000.5.1

Same product

avahi: all records

Other highest-scoring records for the same primary product.

  • CVE-2008-5081The originates_from_local_legacy_unicast_socket function (avahi-core/server.c) in avahi-daemon in Avahi before 0.6.24 allows remote attacker
    38Monitor
  • CVE-2017-6519avahi-daemon in Avahi through 0.6.32 and 0.7 inadvertently responds to IPv6 unicast queries with source addresses that are not on-link, whic
    37Monitor
  • CVE-2021-26720avahi-daemon-check-dns.sh in the Debian avahi package through 0.8-4 is executed as root via /etc/network/if-up.d/avahi-daemon, and allows a
    31Monitor
  • CVE-2011-1002avahi-core/socket.c in avahi-daemon in Avahi before 0.6.29 allows remote attackers to cause a denial of service (infinite loop) via an empty
    29Monitor
  • CVE-2026-24401Avahi has Uncontrolled Recursion in lookup_handle_cname function
    26Monitor
  • CVE-2025-68471Avahi has a reachable assertion in lookup_start
    26Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
avahi avahi0.9-rc4 · descriptionVendor (CNA)
alpine:avahi0.8-r26 · Alpine:v3.24Package registry (OSV)
opensuse:avahi0.8-43.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:avahi-glib20.8-160000.5.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:avahi-qt60.8-160000.5.1 · openSUSE:Leap 16.0Package registry (OSV)
red hat:avahi0:0.9~rc4-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
suse:avahi0.8-160000.5.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:avahi-glib20.8-160000.5.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-6846881 days apartAvahi has a reachable assertion in lookup_multicast_callback
    26Monitor
  • CVE-2025-6847181 days apartAvahi has a reachable assertion in lookup_start
    26Monitor
  • CVE-2025-6827681 days apartAvahi has a reachable assertion in avahi_wide_area_scan_cache
    22Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-617 · Reachable Assertion

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records