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.

The remote SUSE Linux SLES16 / SLES_SAP16 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:22853-1 advisory.

    - CVE-2025-59529: local DoS due to simple protocol server ignoring client limit CLIENTS_MAX (bsc#1255451).

    Changes for avahi:

    - Make /var/lib/avahi-autoipd a ghost dir instead of packaging it      since avahi-autoipd creates it on start (jsc#PED-14836).
    - Use libalternative instead of update-alternatives in TW and SLFO      (jsc#PED-14835).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote openSUSE 16 host has packages installed that are affected by a vulnerability as referenced in the openSUSE- SU-2026:21417-1 advisory.

    - CVE-2025-59529: local DoS due to simple protocol server ignoring client limit CLIENTS_MAX (bsc#1255451).

    Changes for avahi:

    - Make /var/lib/avahi-autoipd a ghost dir instead of packaging it      since avahi-autoipd creates it on start (jsc#PED-14836).
    - Use libalternative instead of update-alternatives in TW and SLFO      (jsc#PED-14835).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES12 host has packages installed that are affected by a vulnerability as referenced in the SUSE- SU-2026:3216-1 advisory.

    This update for avahi fixes the following issue:

    - CVE-2025-59529: local DoS due to simple protocol server ignoring client limit CLIENTS_MAX (bsc#1255451).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:3218-1 advisory.

    This update for avahi fixes the following issue:

    - CVE-2025-59529: local DoS due to simple protocol server ignoring client limit CLIENTS_MAX (bsc#1255451).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

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.

ID	Name	Product	Family	Severity
330296	SUSE SLES16: avahi / avahi-autoipd / avahi-compat-mDNSResponder-devel / etc (SUSE-SU-2026:22853-1)	Nessus	SuSE Local Security Checks	medium
329510	openSUSE 16: avahi / avahi-autoipd / avahi-compat-howl-devel / etc (openSUSE-SU-2026:21417-1)	Nessus	SuSE Local Security Checks	medium
329508	SUSE SLES12: avahi / avahi-compat-howl-devel / avahi-compat-mDNSResponder-devel / etc (SUSE-SU-2026:3216-1)	Nessus	SuSE Local Security Checks	medium
329505	SUSE SLED15: avahi / avahi-autoipd / avahi-compat-howl-devel / etc (SUSE-SU-2026:3218-1)	Nessus	SuSE Local Security Checks	medium
279387	Linux Distros Unpatched Vulnerability : CVE-2025-59529	Nessus	Misc.	medium

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