RHSA-2023:6707 - Security Advisory

Topic

An update for avahi is now available for Red Hat Enterprise Linux 9.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

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.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing the update, avahi-daemon will be restarted automatically.

Affected Products

• Red Hat Enterprise Linux for x86_64 9 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 9.4 x86_64
• Red Hat Enterprise Linux Server - AUS 9.4 x86_64
• Red Hat Enterprise Linux for IBM z Systems 9 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.4 s390x
• Red Hat Enterprise Linux for Power, little endian 9 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.4 ppc64le
• Red Hat Enterprise Linux for ARM 64 9 aarch64
• Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.4 aarch64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.4 ppc64le
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.4 x86_64
• Red Hat CodeReady Linux Builder for x86_64 9 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian 9 ppc64le
• Red Hat CodeReady Linux Builder for ARM 64 9 aarch64
• Red Hat CodeReady Linux Builder for IBM z Systems 9 s390x
• Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support 9.4 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support 9.4 ppc64le
• Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support 9.4 s390x
• Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support 9.4 aarch64
• Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.4 aarch64
• Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.4 s390x

Fixes

• BZ - 1939614 - CVE-2021-3468 avahi: Local DoS by event-busy-loop from writing long lines to /run/avahi-daemon/socket
• BZ - 1946914 - CVE-2021-3502 avahi: reachable assertion in avahi_s_host_name_resolver_start when trying to resolve badly-formatted hostnames
• BZ - 2185911 - CVE-2023-1981 avahi: avahi-daemon can be crashed via DBus

CVEs

• CVE-2021-3468
• CVE-2021-3502
• CVE-2023-1981

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/9.3_release_notes/index