CVE-2021-26720 is a local privilege escalation vulnerability affecting the Debian avahi package (through version 0.8-4), specifically within the avahi-daemon-check-dns.sh script. This flaw allows a local attacker to achieve denial of service or create arbitrary empty files through a symlink attack on files in /run/avahi-daemon. Rated 7.8 HIGH (CVSSv3.1), it requires local access and low privileges, but has high impacts on confidentiality, integrity, and availability. There is no evidence of active exploitation, public exploit code, or significant community discussion, and it is not listed in CISA's KEV catalog.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
<= 0.8-4CPE matchmatch criteria | cpe:2.3:a:avahi:avahi:*:*:*:*:*:*:*:* | ||
9.0CPE matchmatch criteria | cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | ||
10.0CPE matchmatch criteria | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.
CVE-2021-26720
Jun 11, 2024CVE-2021-26720
Dec 14, 2021avahi-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.
Feb 9, 2021