Upstream information
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-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.SUSE information
Overall state of this security issue: Analysis
This issue is currently rated as having moderate severity.
| CVSS detail | CNA (GitHub) | SUSE |
|---|---|---|
| Base Score | 5.5 | 5.5 |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| Attack Vector | Local | Local |
| Attack Complexity | Low | Low |
| Privileges Required | Low | Low |
| User Interaction | None | None |
| Scope | Unchanged | Unchanged |
| Confidentiality Impact | None | None |
| Integrity Impact | None | None |
| Availability Impact | High | High |
| CVSSv3 Version | 3.1 | 3.1 |
| CVSS detail | SUSE |
|---|---|
| Base Score | 6.8 |
| Vector | CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| Attack Vector | Local |
| Attack Complexity | Low |
| Attack Requirements | None |
| Privileges Required | Low |
| User Interaction | None |
| Vulnerable System Confidentiality Impact | None |
| Vulnerable System Integrity Impact | None |
| Vulnerable System Availability Impact | High |
| Subsequent System Confidentiality Impact | None |
| Subsequent System Integrity Impact | None |
| Subsequent System Availability Impact | None |
| CVSSv4 Version | 4.0 |
Status of this issue by product and package
Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.
| Product(s) | Source package | State |
|---|---|---|
| Products under general support and receiving all security fixes. | ||
| SUSE Linux Enterprise Desktop 15 SP6 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 15 SP7 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | avahi | Analysis |
| SUSE Linux Enterprise Micro 5.2 | avahi | Analysis |
| SUSE Linux Enterprise Micro 5.3 | avahi | Analysis |
| SUSE Linux Enterprise Micro 5.4 | avahi | Analysis |
| SUSE Linux Enterprise Micro 5.5 | avahi | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | avahi | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | avahi | Analysis |
| SUSE Linux Enterprise Module for Desktop Applications 15 SP6 | avahi | Analysis |
| SUSE Linux Enterprise Module for Desktop Applications 15 SP7 | avahi | Analysis |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | avahi | Analysis |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | avahi | Analysis |
| SUSE Linux Enterprise Module for Package Hub 15 SP7 | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP6 | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP6-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP7 | avahi | Analysis |
| SUSE Linux Enterprise Server 16.0 | avahi | Unsupported |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP applications 16.0 | avahi | Unsupported |
| SUSE Linux Micro 6.0 | avahi | Analysis |
| SUSE Linux Micro 6.1 | avahi | Analysis |
| SUSE Linux Micro 6.2 | avahi | Unsupported |
| openSUSE Leap 15.6 | avahi | Analysis |
| Products under Long Term Service Pack support and receiving important and critical security fixes. | ||
| SUSE Linux Enterprise High Performance Computing 15 SP3 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | avahi | Analysis |
| SUSE Linux Enterprise Module for Desktop Applications 15 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Module for Desktop Applications 15 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Module for Desktop Applications 15 SP5 | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP5 | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP5-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP5-LTSS Extended Security | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP3-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP4-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP5 | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP5-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | avahi | Analysis |
| SUSE Manager Proxy 4.3 | avahi | Analysis |
| SUSE Manager Proxy LTS 4.3 | avahi | Analysis |
| SUSE Manager Retail Branch Server 4.3 | avahi | Analysis |
| SUSE Manager Retail Branch Server LTS 4.3 | avahi | Analysis |
| SUSE Manager Server 4.3 | avahi | Analysis |
| SUSE Manager Server LTS 4.3 | avahi | Analysis |
| Products past their end of life and not receiving proactive updates anymore. | ||
| HPE Helion OpenStack 8 | avahi | Analysis |
| SUSE CaaS Platform 4.0 | avahi | Analysis |
| SUSE Enterprise Storage 6 | avahi | Analysis |
| SUSE Enterprise Storage 7 | avahi | Analysis |
| SUSE Enterprise Storage 7.1 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 11 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 11 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 12 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 12 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 12 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 15 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 15 SP1 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 15 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 15 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 15 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Desktop 15 SP5 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise High Performance Computing 15-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 | avahi | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | avahi | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Module for Desktop Applications 15 | avahi | Analysis |
| SUSE Linux Enterprise Module for Desktop Applications 15 SP1 | avahi | Analysis |
| SUSE Linux Enterprise Module for Desktop Applications 15 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Module for Package Hub 15 | avahi | Analysis |
| SUSE Linux Enterprise Module for Package Hub 15 SP1 | avahi | Analysis |
| SUSE Linux Enterprise Module for Package Hub 15 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Module for Package Hub 15 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Module for Package Hub 15 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Point of Sale 11 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Point of Sale 12 SP2-CLIENT | avahi | Analysis |
| SUSE Linux Enterprise Real Time 15 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Real Time 15 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Real Time 15 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Server 11 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Server 11 SP3-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 11 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Server 11 SP4 LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 11 SP4-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP2-BCL | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP2-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP2-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP3-BCL | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP3-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP3-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP4-ESPOS | avahi | Analysis |
| SUSE Linux Enterprise Server 12 SP4-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 15 | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP1 | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP1-BCL | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP1-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP2-BCL | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP2-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server 15 SP3-BCL | avahi | Analysis |
| SUSE Linux Enterprise Server 15-LTSS | avahi | Analysis |
| SUSE Linux Enterprise Server for Raspberry Pi 12 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 11 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 11 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 12 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 12 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | avahi | Analysis |
| SUSE Linux Enterprise Software Development Kit 11 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Software Development Kit 11 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Software Development Kit 12 SP2 | avahi | Analysis |
| SUSE Linux Enterprise Software Development Kit 12 SP3 | avahi | Analysis |
| SUSE Linux Enterprise Software Development Kit 12 SP4 | avahi | Analysis |
| SUSE Linux Enterprise Software Development Kit 12 SP5 | avahi | Analysis |
| SUSE Manager Proxy 4.0 | avahi | Analysis |
| SUSE Manager Proxy 4.1 | avahi | Analysis |
| SUSE Manager Proxy 4.2 | avahi | Analysis |
| SUSE Manager Retail Branch Server 4.0 | avahi | Analysis |
| SUSE Manager Retail Branch Server 4.1 | avahi | Analysis |
| SUSE Manager Retail Branch Server 4.2 | avahi | Analysis |
| SUSE Manager Server 4.0 | avahi | Analysis |
| SUSE Manager Server 4.1 | avahi | Analysis |
| SUSE Manager Server 4.2 | avahi | Analysis |
| SUSE OpenStack Cloud 7 | avahi | Analysis |
| SUSE OpenStack Cloud 8 | avahi | Analysis |
| SUSE OpenStack Cloud 9 | avahi | Analysis |
| SUSE OpenStack Cloud Crowbar 8 | avahi | Analysis |
| SUSE OpenStack Cloud Crowbar 9 | avahi | Analysis |
| openSUSE Leap 15.3 | avahi | Analysis |
| openSUSE Leap 15.4 | avahi | Analysis |
| openSUSE Leap 15.5 | avahi | Analysis |
| openSUSE Leap Micro 5.2 | avahi | Analysis |
| openSUSE Leap Micro 5.3 | avahi | Analysis |
| openSUSE Leap Micro 5.4 | avahi | Analysis |
| openSUSE Leap Micro 5.5 | avahi | Analysis |
| Products at an unknown state of their lifecycle. | ||
| SUSE Linux Enterprise Server for SAP Applications 16.0 | avahi | Unsupported |
| Container Status | ||
| suse/sle-micro-rancher/5.2 suse/sle-micro-rancher/5.3 suse/sle-micro-rancher/5.4 suse/sle-micro/5.5 | avahi | Analysis |
SUSE Timeline for this CVE
CVE page created: Fri Dec 19 00:04:20 2025CVE page last modified: Tue Dec 23 12:31:58 2025