CVE-2021-26720
First published: Wed Feb 17 2021(Updated: )
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.
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Avahi Avahi | <=0.8-4 | |
| Debian Debian Linux | =9.0 | |
| Debian Debian Linux | =10.0 | |
| debian/avahi | 0.8-5+deb11u2 0.8-10 0.8-13 |
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Reference Links
- https://www.openwall.com/lists/oss-security/2021/02/15/2
- https://security-tracker.debian.org/tracker/CVE-2021-26720
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=982796
- https://bugs.launchpad.net/ubuntu/+source/avahi/+bug/1870824
- https://bugzilla.suse.com/show_bug.cgi?id=1180827
- https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html
- https://metadata.ftp-master.debian.org/changelogs/main/a/avahi/avahi_0.8-4_changelog
- https://packages.debian.org/bullseye/avahi-daemon
- https://packages.debian.org/buster/avahi-daemon
- https://packages.debian.org/sid/avahi-daemon
Frequently Asked Questions
What is CVE-2021-26720?
CVE-2021-26720 is a vulnerability in the avahi package in Debian that 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.
What is the severity of CVE-2021-26720?
CVE-2021-26720 has a severity value of 7.8 (High).
How does CVE-2021-26720 affect the avahi package?
CVE-2021-26720 affects avahi packages through version 0.8-4.
How can I fix CVE-2021-26720?
To fix CVE-2021-26720, upgrade to avahi package version 0.8-5+deb11u2 or later.
Where can I find more information about CVE-2021-26720?
You can find more information about CVE-2021-26720 on the Openwall website and the Debian security tracker.
- collector/nvd-index
- agent/references
- agent/type
- collector/mitre-cve
- source/MITRE
- collector/security-tracker-debian
- source/Debian
- agent/software-canonical-lookup
- agent/author
- agent/last-modified-date
- agent/severity
- agent/weakness
- agent/softwarecombine
- agent/event
- agent/tags
- agent/first-publish-date
- agent/description
- vendor/avahi
- canonical/avahi avahi
- version/avahi avahi/0.8-4
- vendor/debian
- canonical/debian debian linux
- version/debian debian linux/9.0
- version/debian debian linux/10.0
- package-manager/debian