CVE-2021-3468

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.

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.

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.

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. This enables you to plug your laptop or computer into a network and instantly be able to view other people who you can chat with, find printers to print to or find files being shared.

Security Fix(es):

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 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.

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 AlmaLinux Release Notes linked from the References section.

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_dns_packet_append_record (CVE-2023-38469)
• avahi: Reachable assertion in avahi_escape_label (CVE-2023-38470)
• avahi: Reachable assertion in dbus_set_host_name (CVE-2023-38471)
• avahi: Reachable assertion in avahi_rdata_parse (CVE-2023-38472)
• avahi: Reachable assertion in avahi_alternative_host_name (CVE-2023-38473)

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.

• CVE-2021-3468: handle termination event on avahi Unix socket to prevent infinite loop
• CVE-2023-1981: prevent avahi daemon crash by emitting an error if the requested D-Bus service is not found
• CVE-2021-3502: fix avahi-daemon crashing from NULL pointer assertions
• CVE-2023-38469: reject overly long TXT resource records to prevent reachable assertion in avahi_dns_packet_append_record
• CVE-2023-38470: ensure each label is at least one byte long in avahi_normalize_name() to prevent reachable assertion in avahi_escape_label()
• CVE-2023-38471: fix creating invalid escape sequence in dbus_set_host_name function
• CVE-2023-38472: ensure avahi_rdata_parse() has valid rdata before parsing to prevent reachable assertion
• CVE-2023-38473: normalize input in avahi_alternative_host_name() to prevent reachable assertion due to unescaped dot handling

Avoid infinite loop by handling HUP event in client_work. (CVE-2021-3468)

This update for avahi fixes the following issues:

• CVE-2021-3468: avoid infinite loop by handling HUP event in client_work (bsc#1184521).

This update was imported from the SUSE:SLE-15-SP1:Update update project.

This update for avahi fixes the following issues:

• CVE-2021-3468: avoid infinite loop by handling HUP event in client_work (bsc#1184521).
• CVE-2021-26720: drop privileges when invoking avahi-daemon-check-dns.sh (bsc#1180827)
• Update avahi-daemon-check-dns.sh from Debian. Our previous version relied on ifconfig, route, and init.d.
• Add sudo to requires: used to drop privileges.

These are all security issues fixed in the avahi-0.8-7.2 package on the GA media of openSUSE Tumbleweed.

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_dns_packet_append_record (CVE-2023-38469)

• avahi: Reachable assertion in avahi_escape_label (CVE-2023-38470)

• avahi: Reachable assertion in dbus_set_host_name (CVE-2023-38471)

• avahi: Reachable assertion in avahi_rdata_parse (CVE-2023-38472)

• avahi: Reachable assertion in avahi_alternative_host_name (CVE-2023-38473)

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.

This update for avahi fixes the following issues:

• CVE-2021-3468: avoid infinite loop by handling HUP event in client_work (bsc#1184521).

This update for avahi fixes the following issues:

• CVE-2021-3468: avoid infinite loop by handling HUP event in client_work (bsc#1184521).

This update for avahi fixes the following issues:

• CVE-2021-3468: avoid infinite loop by handling HUP event in client_work (bsc#1184521).

This update for avahi fixes the following issues:

• CVE-2021-3468: avoid infinite loop by handling HUP event in client_work (bsc#1184521).

This update for avahi fixes the following issues:

• CVE-2021-3468: avoid infinite loop by handling HUP event in client_work (bsc#1184521).
• CVE-2021-26720: drop privileges when invoking avahi-daemon-check-dns.sh (bsc#1180827)
• Update avahi-daemon-check-dns.sh from Debian. Our previous version relied on ifconfig, route, and init.d.
• Add sudo to requires: used to drop privileges.

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)

USN-5008-1 fixed a vulnerability in avahi. This update provides the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.

Original advisory 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.