Linux Distros Unpatched Vulnerability : CVE-2025-59529

medium Nessus Plugin ID 279387

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- 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)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: Medium

ID: 279387

File Name: unpatched_CVE_2025_59529.nasl

Version: 1.4

Type: local

Agent: unix

Family: Misc.

Published: 12/19/2025

Updated: 1/21/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Low

Base Score: 2.1

Temporal Score: 1.9

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

CVSS Score Source: CVE-2025-59529

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 5.2

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:U/RC:C

Vulnerability Information

CPE: p-cpe:/a:centos:centos:avahi-libs, cpe:/o:debian:debian_linux:11.0, p-cpe:/a:centos:centos:avahi-ui, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:centos:centos:avahi-devel, p-cpe:/a:redhat:enterprise_linux:avahi-compat-howl, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:redhat:enterprise_linux:avahi-libs, p-cpe:/a:centos:centos:avahi-ui-gtk3, p-cpe:/a:redhat:enterprise_linux:avahi-qt3, p-cpe:/a:redhat:enterprise_linux:avahi-qt4-devel, cpe:/o:redhat:enterprise_linux:6, p-cpe:/a:redhat:enterprise_linux:python3-avahi, p-cpe:/a:centos:centos:avahi-qt4, p-cpe:/a:centos:centos:python3-avahi, p-cpe:/a:centos:centos:avahi-dnsconfd, p-cpe:/a:centos:centos:avahi-qt3, p-cpe:/a:redhat:enterprise_linux:avahi-autoipd, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:canonical:ubuntu_linux:avahi, p-cpe:/a:redhat:enterprise_linux:avahi-ui, cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:centos:centos:avahi-glib, p-cpe:/a:centos:centos:avahi-gobject-devel, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:centos:centos:avahi-ui-tools, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:redhat:enterprise_linux:avahi-qt3-devel, p-cpe:/a:redhat:enterprise_linux:avahi-gobject, cpe:/o:centos:centos:8, p-cpe:/a:redhat:enterprise_linux:avahi-qt4, p-cpe:/a:redhat:enterprise_linux:avahi-compat-howl-devel, p-cpe:/a:redhat:enterprise_linux:avahi-glib-devel, p-cpe:/a:redhat:enterprise_linux:avahi-gobject-devel, p-cpe:/a:redhat:enterprise_linux:avahi-ui-devel, p-cpe:/a:centos:centos:avahi, p-cpe:/a:centos:centos:avahi-compat-libdns_sd, p-cpe:/a:centos:centos:avahi-ui-devel, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:10, cpe:/o:debian:debian_linux:13.0, cpe:/o:canonical:ubuntu_linux:14.04:-:lts, p-cpe:/a:redhat:enterprise_linux:avahi-tools, p-cpe:/a:redhat:enterprise_linux:avahi, p-cpe:/a:debian:debian_linux:avahi, p-cpe:/a:redhat:enterprise_linux:avahi-compat-libdns_sd-devel, p-cpe:/a:redhat:enterprise_linux:avahi-devel, p-cpe:/a:redhat:enterprise_linux:avahi-glib, p-cpe:/a:centos:centos:avahi-qt3-devel, p-cpe:/a:redhat:enterprise_linux:avahi-dnsconfd, cpe:/o:centos:centos:7, p-cpe:/a:centos:centos:avahi-gobject, p-cpe:/a:redhat:enterprise_linux:avahi-compat-libdns_sd, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:centos:centos:avahi-glib-devel, p-cpe:/a:centos:centos:avahi-compat-howl, p-cpe:/a:redhat:enterprise_linux:avahi-ui-gtk3, p-cpe:/a:centos:centos:avahi-compat-howl-devel, p-cpe:/a:centos:centos:avahi-compat-libdns_sd-devel, p-cpe:/a:centos:centos:avahi-tools, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:centos:centos:avahi-qt4-devel, p-cpe:/a:centos:centos:avahi-autoipd, p-cpe:/a:redhat:enterprise_linux:avahi-ui-tools

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 12/18/2025

Reference Information

CVE: CVE-2025-59529

Detections

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