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Echo: avahi: security update to 0.8-16+e2

medium Tenable Cloud Security Plugin ID 457940

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - 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-rc2, 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. (CVE-2025-59529)

Solution

Update the avahi library and its related packages to version 0.8-16+e2 or later.

See Also

https://advisory.echohq.com/cve/CVE-2025-59529

Plugin Details

Severity: Medium

ID: 457940

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.74

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.6

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2025-59529

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 5

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/29/2025

Vulnerability Publication Date: 12/18/2025

Reference Information

CVE: CVE-2025-59529