CVE-2020-8621

Name: CVE-2020-8621
Creator: NVD / NIST
Published: 2020-08-21T21:15:12.167+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.94%

Last modified Jun 17, 2026

CVE-2020-8621 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 2.94% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.94%

85.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-617

Affected Software

Vendor	Product	Versions
Isc	Bind	>= 9.14.0, <= 9.16.5
Isc	Bind	>= 9.17.0, <= 9.17.3
Opensuse	Leap	15.1
Opensuse	Leap	15.2
Canonical	Ubuntu Linux	16.04
Canonical	Ubuntu Linux	18.04
Canonical	Ubuntu Linux	20.04
Synology	Dns Server	< 2.2.2-5027
Netapp	Steelstore Cloud Integrated Storage	All versions

References

http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00041.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00044.htmlMailing List, Third Party Advisory
https://kb.isc.org/docs/cve-2020-8621Vendor Advisory
https://security.gentoo.org/glsa/202008-19Third Party Advisory
https://security.netapp.com/advisory/ntap-20200827-0003/Third Party Advisory
https://usn.ubuntu.com/4468-1/Third Party Advisory
https://www.synology.com/security/advisory/Synology_SA_20_19Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00041.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00044.htmlMailing List, Third Party Advisory
https://kb.isc.org/docs/cve-2020-8621Vendor Advisory
https://security.gentoo.org/glsa/202008-19Third Party Advisory
https://security.netapp.com/advisory/ntap-20200827-0003/Third Party Advisory
https://usn.ubuntu.com/4468-1/Third Party Advisory
https://www.synology.com/security/advisory/Synology_SA_20_19Third Party Advisory

Timeline

Published: Aug 21, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-8621?

How severe is CVE-2020-8621?

CVE-2020-8621 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.94% probability of exploitation in the next 30 days.

How do I fix CVE-2020-8621?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-8621?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST