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CVE-2020-8623

27
FAUCET Score

CVE-2020-8623 is a high-severity denial-of-service vulnerability affecting multiple versions of ISC BIND, including those from Canonical, Debian, Fedora, NetApp, OpenSUSE, and Synology. An unauthenticated attacker can crash a vulnerable BIND server by sending a specially crafted query packet, provided the server was built with "--enable-native-pkcs11" and is signing zones with an RSA key. The CVSS score is 7.5 (High), indicating a network-based attack with low complexity and high impact on availability. Currently, there is no evidence of active exploitation, and no public exploit code (Metasploit, Nuclei, ExploitDB) or significant community discussion has been observed.

Impacted Technologies

VendorProductVersion(s)CPE
>= 9.10.0, <= 9.11.21CPE matchmatch criteria
cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
>= 9.12.1, <= 9.16.5CPE matchmatch criteria
cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
>= 9.17.0, <= 9.17.3CPE matchmatch criteria
cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
9.10.5CPE matchmatch criteria
cpe:2.3:a:isc:bind:9.10.5:s1:*:*:supported_preview:*:*:*
9.11.21CPE matchmatch criteria
cpe:2.3:a:isc:bind:9.11.21:s1:*:*:supported_preview:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
6.40%
Probability of exploitation in next 30 days
EPSS Percentile
92.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0640 is in the 88th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

microsoftpatch availablevia msrc
Product: 19172-16820Fixed in: 9.16.3-2
microsoftpatch availablevia msrc
Product: cm1 bind 9.16.3-2 on CBL Mariner 1.0Fixed in: 9.16.3-2
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: bind-32:9.11.4-26.P2.el7_9.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.6 Extended Update SupportFixed in: bind-32:9.9.4-74.el7_6.5
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.7 Extended Update SupportFixed in: bind-32:9.11.4-9.P2.el7_7.3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: bind-32:9.11.20-5.el8
View patch

Vendor Advisories (2)

redhatCVE-2020-8623Moderate

bind: remotely triggerable assertion failure in pk11.c

Aug 20, 2020
microsoft2020-Aug/CVE-2020-8623Important

A flaw in native PKCS#11 code can lead to a remotely triggerable assertion failure in pk11.c

Aug 11, 2020

References

lists.opensuse.org / opensuse-security-announce/2020-10/msg00041.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-10/msg00044.html
Mailing ListThird Party Advisory
kb.isc.org / docs/cve-2020-8623
Vendor Advisory
lists.debian.org / debian-lts-announce/2020/08/msg00053.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/DQN62GBMCIC5AY4KYADGXNKVY6AJKSJE
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/ZKAMJZXR66P6S5LEU4SN7USSNCWTXEXP
security.gentoo.org / glsa/202008-19
Third Party Advisory
security.netapp.com / advisory/ntap-20200827-0003
Third Party Advisory
usn.ubuntu.com / 4468-1
Third Party Advisory
debian.org / security/2020/dsa-4752
Third Party Advisory
synology.com / security/advisory/Synology_SA_20_19
Third Party Advisory