CVE-2020-8618Network attack vector

Client service denial via zone-transfer assertion

Published Jun 17, 2020 · Updated Sep 16, 2024

Reachable assertion in BIND 9 9.16.0 through 9.16.3 allows remote authenticated users to interrupt DNS service via zone transfer. The rdataset.c buffer-boundary assertion is incorrectly triggered when named processes a large response containing specially constructed zone data, causing the server process to fail. Exploitation requires permission to send zone data to an authoritative server, and the bounded consequence is denial of DNS service to clients without confidentiality or integrity impact.

CVSS severity4.9
Medium
EPSS probability1.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in BIND 9 9.16.0 through 9.16.3 allows remote authenticated users to interrupt DNS service via zone transfer. The rdataset.c buffer-boundary assertion is incorrectly triggered when named processes a large response containing specially constructed zone data, causing the server process to fail. Exploitation requires permission to send zone data to an authoritative server, and the bounded consequence is denial of DNS service to clients without confidentiality or integrity impact.

The record

CVE
CVE-2020-8618
Published
Jun 17, 2020
Updated
Sep 16, 2024
Vendor
Internet Systems Consortium
Product
BIND 9
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 17, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=9.16.0 -> 9.16.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Internet Systems Consortium · BIND 9version=9.16.0 -> 9.16.3

Published CVSS scores

4.9NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
4.3Internet Systems ConsortiumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
4.0NVDAV:N/AC:L/Au:S/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Endpoint Denial of Service: Application or Protocol Weakness

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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