CVE-2026-70091Network attack vector

Network service interruption via DNS race condition

Published Sep 8, 2026 · Updated Sep 9, 2026

A race condition in Microsoft Windows DNS allows remote attackers to interrupt DNS service by sending network traffic to an affected system. Microsoft has not disclosed the shared resource, competing operations, or packet sequence that triggers the synchronization failure. Exploitation requires no authentication or user interaction, but it has high complexity and affects service availability only.

CVSS severity5.9
Medium
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in Microsoft Windows DNS allows remote attackers to interrupt DNS service by sending network traffic to an affected system. Microsoft has not disclosed the shared resource, competing operations, or packet sequence that triggers the synchronization failure. Exploitation requires no authentication or user interaction, but it has high complexity and affects service availability only.

The record

CVE
CVE-2026-70091
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
Microsoft
Product
Windows Server 2019
Classifications
CWE-362, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2026Record 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=10.0.17763.0 <10.0.17763.9245

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Server 2019version=10.0.17763.0 <10.0.17763.9245
Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.33438
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.9512
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.9200.0 <6.2.9200.26349
Microsoft · Windows Server 2012version=6.2.9200.0 <6.2.9200.26349
Microsoft · Windows Server 2016version=10.0.14393.0 <10.0.14393.9512
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.9600.0 <6.3.9600.23397
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.9245
Microsoft · Windows 10 Version 1607version=10.0.14393.0 <10.0.14393.9512
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.5622
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.33438
Microsoft · Windows 10 Version 1809version=10.0.17763.0 <10.0.17763.9245
Microsoft · Windows Server 2012 R2version=6.3.9600.0 <6.3.9600.23397

Published CVSS scores

5.9MicrosoftCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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