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CVE-2021-26720

HIGH
7.8
CVSS Score
Published: February 17, 2021 at 09:19 PM UTC
Updated: June 17, 2026 at 03:43 AM UTC
2 products affected across 2 vendorsDebian LinuxAvahi

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Severity
HIGH7.8
Exploit prediction
EPSS 0.4%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (10)

x_refsource_MISCMailing ListThird Party Advisory
Source: [email protected]
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=982796
x_refsource_MISCIssue TrackingThird Party Advisory
Source: [email protected]
https://bugs.launchpad.net/ubuntu/+source/avahi/+bug/1870824
x_refsource_MISCIssue TrackingThird Party Advisory
Source: [email protected]
https://bugzilla.suse.com/show_bug.cgi?id=1180827
Mailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html
x_refsource_MISCBroken LinkThird Party Advisory
Source: [email protected]
https://metadata.ftp-master.debian.org/changelogs/main/a/avahi/avahi_0.8-4_changelog
x_refsource_MISCProductThird Party Advisory
Source: [email protected]
https://packages.debian.org/bullseye/avahi-daemon
x_refsource_MISCProductThird Party Advisory
Source: [email protected]
https://packages.debian.org/buster/avahi-daemon
x_refsource_MISCProductThird Party Advisory
Source: [email protected]
https://packages.debian.org/sid/avahi-daemon

CVSS

7.8HIGH[email protected]
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-59

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