USN-5008-1: Avahi vulnerabilities

Releases

• Ubuntu 21.04
• Ubuntu 20.10
• Ubuntu 20.04 LTS
• Ubuntu 18.04 ESM

Packages

• avahi - IPv4LL network address configuration daemon

Details

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)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 21.04

• libavahi-core7 - 0.8-5ubuntu3.1
• avahi-daemon - 0.8-5ubuntu3.1

Ubuntu 20.10

• libavahi-core7 - 0.8-3ubuntu1.1
• avahi-daemon - 0.8-3ubuntu1.1

Ubuntu 20.04

• libavahi-core7 - 0.7-4ubuntu7.1
• avahi-daemon - 0.7-4ubuntu7.1

Ubuntu 18.04

• libavahi-core7 - 0.7-3.1ubuntu1.3
• avahi-daemon - 0.7-3.1ubuntu1.3

In general, a standard system update will make all the necessary changes.

References

• CVE-2021-3468
• CVE-2021-3502

Related notices

• USN-5008-2: libavahi-glib1, avahi-ui-utils, avahi-utils, avahi-dnsconfd, libavahi-ui-gtk3-0, libavahi-common-data, avahi-daemon, libavahi-qt4-dev, libavahi-ui-gtk3-dev, libavahi-client3, python-avahi, libavahi-common-dev, libavahi-compat-libdnssd-dev, avahi-discover, libavahi-core7-udeb, libavahi-client-dev, avahi-autoipd, libavahi-gobject0, libavahi-ui0, libavahi-qt4-1, libavahi-compat-libdnssd1, avahi, libavahi-common3, libavahi-core-dev, libavahi-glib-dev, libavahi-core7, libavahi-ui-dev, libavahi-common3-udeb, libavahi-gobject-dev