CVE-2021-26720

Published: 17 February 2021

avahi-daemon-check-dns.sh in the Debian avahi package through 0.8-4 is executed as root via /etc/network/if-up.d/avahi-daemon, and allows a local attacker to cause a denial of service or create arbitrary empty files via a symlink attack on files under /run/avahi-daemon. NOTE: this only affects the packaging for Debian GNU/Linux (used indirectly by SUSE), not the upstream Avahi product.

Priority

Low

CVSS 3 base score: 7.8

Status

Package Release Status
avahi
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Not vulnerable
(0.8-3ubuntu2)
Ubuntu 20.10 (Groovy Gorilla) Not vulnerable
(0.8-3ubuntu1)
Ubuntu 20.04 LTS (Focal Fossa) Not vulnerable
(0.7-4ubuntu7)
Ubuntu 18.04 LTS (Bionic Beaver) Needed

Ubuntu 16.04 LTS (Xenial Xerus) Needed

Ubuntu 14.04 ESM (Trusty Tahr) Needed

Notes

AuthorNote
mdeslaur
the script was removed in the 0.7-4ubuntu7 package in focal.
for bionic and earlier, we can't simply remove the script as
libnss-mdns is too old there.

References

Bugs