A flaw was found in avahi 0.8-5. A reachable assertion is present in avahi_s_host_name_resolver_start function allowing a local attacker to crash the avahi service by requesting hostname resolutions through the avahi socket or dbus methods for invalid hostnames. The highest threat from this vulnerability is to the service availability.

The AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2025:1743675732 advisory.

  - A flaw was found in avahi in versions 0.6 up to 0.8. The event used to signal the termination of the     client connection on the avahi Unix socket is not correctly handled in the client_work function, allowing     a local attacker to trigger an infinite loop. The highest threat from this vulnerability is to the     availability of the avahi service, which becomes unresponsive after this flaw is triggered.
    (CVE-2021-3468)

  - A flaw was found in avahi 0.8-5. A reachable assertion is present in avahi_s_host_name_resolver_start     function allowing a local attacker to crash the avahi service by requesting hostname resolutions through     the avahi socket or dbus methods for invalid hostnames. The highest threat from this vulnerability is to     the service availability. (CVE-2021-3502)

  - A vulnerability was found in the avahi library. This flaw allows an unprivileged user to make a dbus call,     causing the avahi daemon to crash. (CVE-2023-1981)

  - A vulnerability was found in Avahi, where a reachable assertion exists in avahi_dns_packet_append_record.
    (CVE-2023-38469)

  - A vulnerability was found in Avahi. A reachable assertion exists in the avahi_escape_label() function.
    (CVE-2023-38470)

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

The Rocky Linux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the CIQ ciqsa-2026_0387 advisory.

    This advisory aggregates security fixes for the avahi SRPM in CIQ LTS 9.2. It addresses 5 CVEs:
    CVE-2021-3468, CVE-2011-1002, CVE-2023-1981, CVE-2006-6870, CVE-2021-3502.

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

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

The remote MiracleLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2023-6723:02 advisory.

    * avahi: Local DoS by event-busy-loop from writing long lines to /run/avahi-daemon/socket (CVE-2021-3468)
      * avahi: reachable assertion in avahi_s_host_name_resolver_start when trying to resolve badly-formatted     hostnames (CVE-2021-3502)
      * avahi: avahi-daemon can be crashed via DBus (CVE-2023-1981)

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

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

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

  - A flaw was found in avahi 0.8-5. A reachable assertion is present in avahi_s_host_name_resolver_start
    function allowing a local attacker to crash the avahi service by requesting hostname resolutions through
    the avahi socket or dbus methods for invalid hostnames. The highest threat from this vulnerability is to
    the service availability. (CVE-2021-3502)

The remote Oracle Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2023-6707 advisory.

    - Fix CVE-2023-1981 (#2186689)
    - Fix CVE-2021-3502 (#1949949)

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

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

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2023:6707 advisory.

    Avahi is an implementation of the DNS Service Discovery and Multicast DNS specifications for Zero     Configuration Networking. It facilitates service discovery on a local network. Avahi and Avahi-aware     applications allow you to plug your computer into a network and, with no configuration, view other people     to chat with, view printers to print with, and find shared files on other computers.

    Security Fix(es):

    * avahi: Local DoS by event-busy-loop from writing long lines to /run/avahi-daemon/socket (CVE-2021-3468)

    * avahi: reachable assertion in avahi_s_host_name_resolver_start when trying to resolve badly-formatted     hostnames (CVE-2021-3502)

    * avahi: avahi-daemon can be crashed via DBus (CVE-2023-1981)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

    Additional Changes:

    For detailed information on changes in this release, see the Red Hat Enterprise Linux 9.3 Release Notes     linked from the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

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

The remote Ubuntu 18.04 LTS / 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5008-1 advisory.

    Thomas Kremer discovered that Avahi incorrectly handled termination signals on the Unix socket. A local     attacker could possibly use this issue to cause Avahi to hang, resulting in a denial of service. This     issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, and Ubuntu 20.10. (CVE-2021-3468)

    It was discovered that Avahi incorrectly handled certain hostnames. A local attacker could possibly use     this issue to cause Avahi to crash, resulting in a denial of service. This issue only affected Ubuntu     20.10 and Ubuntu 21.04. (CVE-2021-3502)

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

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

ID	Name	Product	Family	Type	Severity
361906	AlmaLinux 9.2 [TuxCare] Security Update: avahi / avahi-autoipd / avahi-compat-howl / avahi-compat-howl-devel / etc Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2025:1743675732)	Nessus	Alma Linux Local Security Checks	Local	medium
355748	Rocky Linux 9.2 [CIQ] Security Update: avahi / avahi-autoipd / avahi-autoipd-debuginfo / avahi-compat-howl / etc Multiple Vulnerabilities (ciqsa-2026_0387)	Nessus	Rocky Linux Local Security Checks	Local	medium
292601	MiracleLinux 9 : avahi-0.8-15.el9 (AXSA:2023-6723:02)	Nessus	Miracle Linux Local Security Checks	Local	medium
423685	Alpine: multiple avahi packages, multiple py3-avahi packages: security update to 0.8-r5	Tenable Cloud Security	Alpine Linux Local Security Checks	Local	medium
423685	Alpine: multiple avahi packages, multiple py3-avahi packages: security update to 0.8-r5	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	Local	medium
185873	Oracle Linux 9 : avahi (ELSA-2023-6707)	Nessus	Oracle Linux Local Security Checks	Local	medium
185101	RHEL 9 : avahi (RHSA-2023:6707)	Nessus	Red Hat Local Security Checks	Local	medium
403606	Alpine: avahi: security update to 0.8-r5	Tenable Cloud Security	Alpine Linux Local Security Checks	Local	medium
403606	Alpine: avahi: security update to 0.8-r5	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	Local	medium
151452	Ubuntu 18.04 LTS / 20.04 LTS : Avahi vulnerabilities (USN-5008-1)	Nessus	Ubuntu Local Security Checks	Local	medium

Detections

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CVE-2021-3502

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Tenable Plugins

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