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TI-2026-27157 Aliases CVE-2026-34933

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

Priority MEDIUM 58CWE-617Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 1 fixed, 6 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-617.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00207 10th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix Partial avahi (avahi): 0.9-rc4Red Hat: 1 advisoryRed Hat: 1 fixed, 6 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
avahiavahibefore 0.9-rc40.9-rc4Patch availableCNA
  • avahi Vendoravahi Affected before 0.9-rc4 Fixed in 0.9-rc4 Patch available CNA

CPE configurations NVD · 4

CPEVersionsRoleVendor
cpe:2.3:a:avahi:avahi:*:*:*:*:*:*:*:*before 0.9Vulnerableavahi
cpe:2.3:a:avahi:avahi:0.9:rc1:*:*:*:*:*:*0.9 rc1Vulnerableavahi
cpe:2.3:a:avahi:avahi:0.9:rc2:*:*:*:*:*:*0.9 rc2Vulnerableavahi
cpe:2.3:a:avahi:avahi:0.9:rc3:*:*:*:*:*:*0.9 rc3Vulnerableavahi
  • cpe:2.3:a:avahi:avahi:*:*:*:*:*:*:*:* Versions before 0.9 Vulnerable ·avahi
  • cpe:2.3:a:avahi:avahi:0.9:rc1:*:*:*:*:*:* Versions 0.9 rc1 Vulnerable ·avahi
  • cpe:2.3:a:avahi:avahi:0.9:rc2:*:*:*:*:*:* Versions 0.9 rc2 Vulnerable ·avahi
  • cpe:2.3:a:avahi:avahi:0.9:rc3:*:*:*:*:*:* Versions 0.9 rc3 Vulnerable ·avahi

Remediation

  • Fix · CNA avahi (avahi) Fixed in 0.9-rc4

Red Hat 1 advisory

  • RHSA-2026:11316 Released 2026-04-28 · Red Hat rating Moderate
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images avahi-0.9~rc4-0.1.hum1@aarch64, avahi-0.9~rc4-0.1.hum1@src, avahi-0.9~rc4-0.1.hum1@x86_64 +47

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 6AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat Hardened ImagesFixed RHSA-2026:11316

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-34933

References

Exploit 2

Patch 2

  • TI-2025-37060 Avahi: simple protocol server ignores accepts unlimited connections and logs failures without limit CVSS 3.1MEDIUM 5.5
  • TI-2008-04834 The originates_from_local_legacy_unicast_socket function (avahi-core/server.c) in… CVSS 2.0MEDIUM 5.0
  • TI-2017-04303 avahi-daemon in Avahi through 0.6.32 and 0.7 inadvertently responds to IPv6 unicast… CVSS 3.1CRITICAL 9.1
  • TI-2011-00862 avahi-core/socket.c in avahi-daemon in Avahi before 0.6.29 allows remote attackers to… CVSS 2.0MEDIUM 5.0
  • TI-2021-08399 avahi-daemon-check-dns.sh in the Debian avahi package through 0.8-4 is executed as root… CVSS 3.1HIGH 7.8
  • TI-2026-19669 Avahi has Uncontrolled Recursion in lookup_handle_cname function CVSS 3.1MEDIUM 6.5
See all 23 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences