Skip to main content
CVE-2025-59529VulnerabilityPublished Updated

Avahi:

Affects avahiSource GCVE Database

0
Authoritative record:CVE-2025-59529· Medium 5.5

Not known to be exploited · CVSS 5.5 Medium.

Data as of 28 Oct 2026, 22:28 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 18 Dec 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: evidence found.

    CISA SSVC: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by GitHub, Inc.

    , 92 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. CISA SSVC assessment

    proof of concept public

    , 16 minutes after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.10avahipkg:deb/ubuntu/avahi?arch=source&distro=stonkingOther threatsAffected
  • =0.8-18ubuntu1
  • =0.8-18ubuntu1.1
Fixed in–
Ubuntu 26.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=resoluteOther threatsAffected
  • 0.8-16ubuntu3 – 0.8-18ubuntu1.1
5 affected builds
Fixed in–
Ubuntu 25.10avahipkg:deb/ubuntu/avahi?arch=source&distro=questingOther threatsAffected
  • 0.8-16ubuntu2 – 0.8-16ubuntu3.2
4 affected builds
Fixed in–
Ubuntu 24.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=nobleOther threatsAffected
  • 0.8-10ubuntu1 – 0.8-13ubuntu6.2
8 affected builds
Fixed in–
Ubuntu 22.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=jammyOther threatsAffected
  • 0.8-5ubuntu4 – 0.8-5ubuntu5.5
7 affected builds
Fixed in–
Ubuntu Pro 20.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=esm-infra/focalOther threatsAffected
  • 0.7-4ubuntu5 – 0.7-4ubuntu7.3+esm2
8 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In versions up to and including 0.9-rc5, the simple protocol server ignores the documented client limit and accepts unlimited connections, allowing for easy local DoS. Although `CLIENTS_MAX` is defined, `server_work()` unconditionally `accept()`s and `client_new()` always appends the new client and increments `n_clients`. There is no check against the limit. When client cannot be accepted as a result of maximal socket number of avahi-daemon, it logs unconditionally error per each connection. Unprivileged local users can exhaust daemon memory and file descriptors, causing a denial of service system-wide for mDNS/DNS-SD. Exhausting local file descriptors causes increased system load caused by logging errors of each of request. Overloading prevents glibc calls using nss-mdns plugins to resolve `*.local.` names and link-local addresses. As of time of publication, no known patched versions are available, but a candidate fix is available in pull request 808, and some workarounds are available. Simple clients are offered for nss-mdns package functionality. It is not possible to disable the unix socket `/run/avahi-daemon/socket`, but resolution requests received via DBus are not affected directly. Tools avahi-resolve, avahi-resolve-address and avahi-resolve-host-name are not affected, they use DBus interface. It is possible to change permissions of unix socket after avahi-daemon is started. But avahi-daemon does not provide any configuration for it. Additional access restrictions like SELinux can also prevent unwanted tools to access the socket and keep resolution working for trusted users.

References

Community reviews

Loading reviews…