SB20260518100 - Ubuntu update for avahi

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Main Vulnerability Database SB20260518100

SB20260518100 - Ubuntu update for avahi

Published: May 18, 2026

Security Bulletin ID SB20260518100
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 2
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 50% Low 50%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 2 vulnerabilities.


1) Uncontrolled Recursion (CVE-ID: CVE-2026-24401)

CWE-ID: CWE-674 - Uncontrolled Recursion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to uncontrolled recursion in lookup_handle_cname. A remote attacker can cause a denial of service condition on the target system.


2) Reachable assertion (CVE-ID: CVE-2026-34933)

CWE-ID: CWE-617 - Reachable Assertion

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to reachable assertion in transport_flags_from_domain() when handling D-Bus method calls with conflicting publish flags. A local user can send a specially crafted D-Bus method call to cause a denial of service.

The issue can be triggered through org.freedesktop.Avahi.EntryGroup methods that accept a flags parameter, and repeated crashes can result in persistent service disruption if the daemon is automatically restarted.


Remediation

Install update from vendor's website.

References