CVE-2020-8621

mediumpriority · track · 31EPSS 0.030 · 87 %ileEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.97% (87th) EPSS

CVSS 4.3 · medium

Is it mine?

17 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

In BIND 9.14.0 -> 9.16.5, 9.17.0 -> 9.17.3, If a server is configured with both QNAME minimization and 'forward first' then an attacker who can send queries to it may be able to trigger the condition that will cause the server to crash. Servers that 'forward only' are not affected.

cvss

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

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.3–7.5

v2.04.3mediumAV:N/AC:M/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · security-officer@isc.orgexploitability 3.9 · impact 3.6

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-617USprimaryCWE-20US

affected products (17)

Products and version ranges known to be affected.

ISC BIND99.14.0 → *enisa_euvdEU
Canonical Ltd. Ubuntu≤ 18.04 LTSfstec_bduRU
Canonical Ltd. Ubuntu≤ 16.04 ESMfstec_bduRU
Canonical Ltd. Ubuntu≤ 20.04 LTSfstec_bduRU
Internet Systems Consortium BIND9.14.0 → 9.16.5fstec_bduRU
Internet Systems Consortium BIND9.17.0 → 9.17.3fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.1fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.2fstec_bduRU
canonical ubuntu linux= 16.04nvdUScpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:*:*:*:*
canonical ubuntu linux= 18.04nvdUScpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:*:*:*:*
canonical ubuntu linux= 20.04nvdUScpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:*:*:*:*
isc bind9.14.0 → 9.16.5nvdUScpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
isc bind9.17.0 → 9.17.3nvdUScpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
netapp steelstore cloud integrated storageall versionsnvdUScpe:2.3:a:netapp:steelstore_cloud_integrated_storage:*:*:*:*:*:*:*:*
opensuse leap= 15.1nvdUScpe:2.3:o:opensuse:leap:*:*:*:*:*:*:*:*
opensuse leap= 15.2nvdUScpe:2.3:o:opensuse:leap:*:*:*:*:*:*:*:*
synology dns server< 2.2.2-5027nvdUScpe:2.3:a:synology:dns_server:*:*:*:*:*:*:*:*

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 2020-08-21modified 2026-06-17

related (1,031)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2015-5477US	high7.8OT critical	99.6% (100th)	KEV	2015-07-29
named in ISC BIND 9.x before 9.9.7-P2 and 9.10.x before 9.10.2-P3 allows remote attackers to cause a denial of service (REQUIRE assertion failure and daemon exit) via TKEY queries.
CVE-2016-2776US	high7.5	89.5% (100th)	Exploit	2016-09-28
buffer.c in named in ISC BIND 9 before 9.9.9-P3, 9.10.x before 9.10.4-P3, and 9.11.x before 9.11.0rc3 does not properly construct responses, which allows remote attackers to cause…
CVE-2021-25216US	critical9.8	83.0% (100th)	—	2021-04-29
In BIND 9.5.0 -> 9.11.29, 9.12.0 -> 9.16.13, and versions BIND 9.11.3-S1 -> 9.11.29-S1 and 9.16.8-S1 -> 9.16.13-S1 of BIND Supported Preview Edition, as well as release versions 9.…
CVE-2020-8617US	medium5.9	93.4% (100th)	Exploit	2020-05-19
Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG…
CVE-2018-5740US	high7.5	59.6% (99th)	Exploit	2019-01-16
"deny-answer-aliases" is a little-used feature intended to help recursive server operators protect end users against DNS rebinding attacks, a potential method of circumventing the…

+1026 more

references (26)

External citations — patches, advisories, analysis.

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