CVE-2020-8620

In BIND 9.15.6 -> 9.16.5, 9.17.0 -> 9.17.3, An attacker who can establish a TCP connection with the server and send data on that connection can exploit this to trigger the assertion failure, causing the server to exit.

Published: 2020-08-21 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-8620 is rated Moderate Risk (56.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.66%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-8620

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 8.37% 3.66% -4.71%
2 2026-02-27 7.29% 8.37% +1.08%
3 2025-12-28 — 7.29% —

Full EPSS history (27 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-8620

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2020-8620

OS Trackers for CVE-2020-8620

vendor priority summary link
alpine high CVE-2020-8620: 1 source package rows (bind); 15 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 5. https://security.alpinelinux.org/vuln/CVE-2020-8620
debian not yet assigned CVE-2020-8620 not yet assigned priority: Debian including 1 source packages (bind9), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-8620
gentoo normal CVE-2020-8620: 1 GLSA(s) (202008-19), 1 atom(s) (net-dns/bind); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-8620
redhat medium — https://access.redhat.com/security/cve/CVE-2020-8620
suse high CVE-2020-8620 severity important: SUSE including 479 source package names (0.1.0:sysuser-shadow-2.0-4.2.8, 0.1.75:sysuser-shadow-2.0-4.2.8, …), 689 product×package rows across 182 product lines (Container bci/bci-init, Container bci/dotnet-aspnet, … (182 product lines)): Fixed 498, Known Affected 157, Known Not Affected 34. https://www.suse.com/security/cve/CVE-2020-8620/
ubuntu medium CVE-2020-8620 medium priority: Ubuntu including 1 source packages (bind9), 5 status rows across 5 suites (bionic, focal, trusty, upstream, xenial): not-affected 3, needs-triage 1, released 1. https://ubuntu.com/security/CVE-2020-8620

Affected software / configurations for CVE-2020-8620

Vendor Product Version Raw CPE
isc bind >= 9.15.6, <= 9.16.5 cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
isc bind >= 9.17.0, <= 9.17.3 cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
isc bind 9.9.12 cpe:2.3:a:isc:bind:9.9.12:s1:*:*:supported_preview:*:*:*
isc bind 9.9.13 cpe:2.3:a:isc:bind:9.9.13:s1:*:*:supported_preview:*:*:*
isc bind 9.11.3 cpe:2.3:a:isc:bind:9.11.3:s1:*:*:supported_preview:*:*:*
isc bind 9.11.21 cpe:2.3:a:isc:bind:9.11.21:s1:*:*:supported_preview:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
opensuse leap 15.2 cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*
netapp steelstore_cloud_integrated_storage — cpe:2.3:a:netapp:steelstore_cloud_integrated_storage:-:*:*:*:*:*:*:*
canonical ubuntu_linux 12.04 cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*

References for CVE-2020-8620

cvelogic Threat Intelligence