CVE-2021-40469Public exploitNetwork attack vector

Remote code execution via writable DNS plug-in path

Published Oct 13, 2021 · Updated Aug 4, 2024

Remote code execution in Microsoft Windows DNS Server allows remote authenticated users to execute code through the DNS management interface. The ServerLevelPluginDll operation lets DNSAdmins set an unchecked DLL path that the DNS service loads as SYSTEM when restarted. Exploitation requires DNSAdmins-equivalent write access and a server running the DNS Server role, and a bad DLL path can keep the service from restarting.

CVSS severity7.2
High
EPSS probability7.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Remote code execution in Microsoft Windows DNS Server allows remote authenticated users to execute code through the DNS management interface. The ServerLevelPluginDll operation lets DNSAdmins set an unchecked DLL path that the DNS service loads as SYSTEM when restarted. Exploitation requires DNSAdmins-equivalent write access and a server running the DNS Server role, and a bad DLL path can keep the service from restarting.

The record

CVE
CVE-2021-40469
Published
Oct 13, 2021
Updated
Aug 4, 2024
Vendor
Microsoft
Product
Windows Server 2019
Classifications
T1505
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=10.0.0 <10.0.17763.2237

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Windows Server 2019version=10.0.0 <10.0.17763.2237
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.0 <10.0.14393.4704
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.0 <6.2.9200.23490
Microsoft · Windows Server 2012version=6.2.0 <6.2.9200.23490
Microsoft · Windows Server, version 2004version=10.0.0 <10.0.19041.1288
Microsoft · Windows Server 2016version=10.0.0 <10.0.14393.4704
Microsoft · Windows Server 2008 R2 Service Pack 1version=6.1.0 <6.1.7601.25740
Microsoft · Windows Server 2008 R2 Service Pack 1 (Server Core installation)version=6.0.0 <6.1.7601.25740
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.0 <6.3.9600.20144
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.0 <10.0.17763.2237
Microsoft · Windows Server version 20H2version=10.0.0 <10.0.19042.1288
Microsoft · Windows Server 2008 Service Pack 2version=6.0.0 <6.0.6003.21251
Microsoft · Windows Server 2022version=10.0.0 <10.0.20348.288
Microsoft · Windows Server 2012 R2version=6.3.0 <6.3.9600.20144
Microsoft · Windows Server 2008 Service Pack 2 (Server Core installation)version=6.0.0 <6.0.6003.21251

Published CVSS scores

7.2MicrosoftCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.5NVDAV:N/AC:L/Au:S/C:P/I:P/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 exploitPublished

Weakness, pattern, technique

T1505Server Software Component

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo