{"id":"CVE-2021-26720","details":"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.","modified":"2026-03-15T22:36:57.131262Z","published":"2021-02-17T22:15:12.710Z","related":["CGA-4vq7-pfjp-cg52","SUSE-SU-2021:0551-1","SUSE-SU-2021:0563-1","SUSE-SU-2021:1845-1","openSUSE-SU-2021:0370-1","openSUSE-SU-2021:1845-1","openSUSE-SU-2024:10643-1"],"references":[{"type":"ADVISORY","url":"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=982796"},{"type":"ADVISORY","url":"https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html"},{"type":"ADVISORY","url":"https://metadata.ftp-master.debian.org/changelogs/main/a/avahi/avahi_0.8-4_changelog"},{"type":"ADVISORY","url":"https://packages.debian.org/bullseye/avahi-daemon"},{"type":"ADVISORY","url":"https://packages.debian.org/buster/avahi-daemon"},{"type":"ADVISORY","url":"https://packages.debian.org/sid/avahi-daemon"},{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2021-26720"},{"type":"ADVISORY","url":"https://www.openwall.com/lists/oss-security/2021/02/15/2"},{"type":"REPORT","url":"https://bugs.launchpad.net/ubuntu/+source/avahi/+bug/1870824"},{"type":"REPORT","url":"https://bugzilla.suse.com/show_bug.cgi?id=1180827"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-26720.json","unresolved_ranges":[{"events":[{"introduced":"0"},{"last_affected":"0.8-4"}]},{"events":[{"introduced":"0"},{"last_affected":"9.0"}]},{"events":[{"introduced":"0"},{"last_affected":"10.0"}]},{"events":[{"introduced":"0"},{"last_affected":"0.8-4"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}