CVE-2021-3468 Denial of service in avahi

Medium 5.5 Published Updated

A local attacker can trigger an infinite loop in Avahi by mishandling client connection termination, causing the service to become unresponsive.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Local or same network only
Victim action needed
Not needed
Fix
Available

What is CVE-2021-3468?

CVE-2021-3468 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 2 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-835

Which versions are affected by CVE-2021-3468?

It affects 2 products.

Linux distribution packages (40)
avahi SUSE:Enterprise Storage 6All versions0.7-3.9.1
avahi-glib2 SUSE:Enterprise Storage 6All versions0.7-3.9.1
avahi SUSE:HPE Helion OpenStack 8All versions0.6.32-32.15.1
avahi-glib2 SUSE:HPE Helion OpenStack 8All versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOSAll versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOSAll versions0.7-3.9.1
avahi SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSSAll versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSSAll versions0.7-3.9.1
avahi SUSE:Linux Enterprise Module for Basesystem 15 SP2All versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise Module for Basesystem 15 SP2All versions0.7-3.9.1
avahi SUSE:Linux Enterprise Module for Basesystem 15 SP3All versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise Module for Basesystem 15 SP3All versions0.7-3.9.1
avahi SUSE:Linux Enterprise Module for Desktop Applications 15 SP2All versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise Module for Desktop Applications 15 SP2All versions0.7-3.9.1
avahi SUSE:Linux Enterprise Module for Desktop Applications 15 SP3All versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise Module for Desktop Applications 15 SP3All versions0.7-3.9.1
avahi SUSE:Linux Enterprise Module for Package Hub 15 SP2All versions0.7-3.9.1
avahi SUSE:Linux Enterprise Module for Package Hub 15 SP3All versions0.7-3.9.1
avahi SUSE:Linux Enterprise Server 12 SP2-BCLAll versions0.6.32-32.15.1
avahi-glib2 SUSE:Linux Enterprise Server 12 SP2-BCLAll versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise Server 12 SP3-BCLAll versions0.6.32-32.15.1
avahi-glib2 SUSE:Linux Enterprise Server 12 SP3-BCLAll versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise Server 12 SP3-LTSSAll versions0.6.32-32.15.1
avahi-glib2 SUSE:Linux Enterprise Server 12 SP3-LTSSAll versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise Server 12 SP4-LTSSAll versions0.6.32-32.15.1
avahi-glib2 SUSE:Linux Enterprise Server 12 SP4-LTSSAll versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise Server 12 SP5All versions0.6.32-32.15.1
avahi-glib2 SUSE:Linux Enterprise Server 12 SP5All versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise Server 15 SP1-BCLAll versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise Server 15 SP1-BCLAll versions0.7-3.9.1
avahi SUSE:Linux Enterprise Server 15 SP1-LTSSAll versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise Server 15 SP1-LTSSAll versions0.7-3.9.1
avahi SUSE:Linux Enterprise Server for SAP Applications 12 SP3All versions0.6.32-32.15.1
avahi-glib2 SUSE:Linux Enterprise Server for SAP Applications 12 SP3All versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise Server for SAP Applications 12 SP4All versions0.6.32-32.15.1
avahi-glib2 SUSE:Linux Enterprise Server for SAP Applications 12 SP4All versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise Server for SAP Applications 12 SP5All versions0.6.32-32.15.1
avahi-glib2 SUSE:Linux Enterprise Server for SAP Applications 12 SP5All versions0.6.32-32.15.1
avahi SUSE:Linux Enterprise Server for SAP Applications 15 SP1All versions0.7-3.9.1
avahi-glib2 SUSE:Linux Enterprise Server for SAP Applications 15 SP1All versions0.7-3.9.1

Products include Avahi Avahi, Debian Debian Linux.

How do I fix CVE-2021-3468?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-3468 being exploited?

There is no known exploitation of CVE-2021-3468 in the wild and no public exploit code.

All Debian Debian Linux vulnerabilities

Sources

Also known as ALPINE-CVE-2021-3468, AZL-34548, AZL-6324, DEBIAN-CVE-2021-3468, DLA-3466-1, GHSA-43rm-fv4g-cmj8 and 9 more.

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