CVE-2021-26720

HIGH

avahi < 0.8-4 - Denial of Service and Arbitrary File Creation via Symlink Attack

Title source: llm
STIX 2.1

Description

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.

References (10)

Core 10
Core References
Product, Third Party Advisory x_refsource_misc
https://packages.debian.org/buster/avahi-daemon
Product, Third Party Advisory x_refsource_misc
https://packages.debian.org/sid/avahi-daemon
Product, Third Party Advisory x_refsource_misc
https://packages.debian.org/bullseye/avahi-daemon
Third Party Advisory x_refsource_misc
https://security-tracker.debian.org/tracker/CVE-2021-26720
Issue Tracking, Third Party Advisory x_refsource_misc
https://bugs.launchpad.net/ubuntu/+source/avahi/+bug/1870824
Mailing List, Third Party Advisory x_refsource_misc
https://www.openwall.com/lists/oss-security/2021/02/15/2
Mailing List, Third Party Advisory x_refsource_misc
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=982796
Issue Tracking, Third Party Advisory x_refsource_misc
https://bugzilla.suse.com/show_bug.cgi?id=1180827
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html

Scores

CVSS v3 7.8
EPSS 0.0040
EPSS Percentile 31.1%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-59
Status published
Products (3)
avahi/avahi < 0.8-4
debian/debian_linux 9.0
debian/debian_linux 10.0
Published Feb 17, 2021
Tracked Since Feb 18, 2026