CVE-2021-26720

mediumpriority · track · 31EPSS 0.004 · 34 %ileEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.40% (34th) EPSS

CVSS 4.6 · medium

Is it mine?

10 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-28

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.

cvss

Technical severity, 0–10. One row per scoring source.

7.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.6–7.8

v2.04.6mediumAV:L/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 3.9 · impact 6.4

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 1.8 · impact 5.9

v3.17.8highAV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.17.1highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-59USprimaryCWE-59US

affected products (10)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
The Avahi Project Avahi≤ 0.8-4fstec_bduRU
АО «НТЦ ИТ РОСА» РОСА ХРОМ≤ 12.4fstec_bduRU
ООО «РусБИТех-Астра» Astra Linux Special Edition≤ 1.6 «Смоленск»fstec_bduRU
ООО «РусБИТех-Астра» Astra Linux Special Edition для «Эльбрус»≤ 8.1 «Ленинград»fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 11fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 10fstec_bduRU
avahi avahi≤ 0.8-4nvdUScpe:2.3:a:avahi:avahi:*:*:*:*:*:*:*:*
debian debian linux= 10.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*
debian debian linux= 9.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd NVD CVE.org MITRE

published 2021-02-17modified 2026-06-17

related (2,373)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2026-81963US	high7.8OT critical	0.39% (33rd)	KEV	2026-09-08
Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.
CVE-2026-41091US	—OT critical	8.20% (95th)	KEV	2026-05-20
Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.
CVE-2025-60710US	—OT critical	4.61% (92nd)	KEV	2025-11-11
Improper link resolution before file access ('link following') in Host Process for Windows Tasks allows an authorized attacker to elevate privileges locally.
CVE-2025-48384US	—OT critical	4.38% (91st)	KEV	2025-07-08
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals. When reading…
CVE-2025-21391US	—OT critical	2.28% (83rd)	KEV	2025-02-11
Windows Storage Elevation of Privilege Vulnerability

+2368 more

references (36)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan