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CVE-2026-62817

Windows DNS Server Remote Code Execution Vulnerability

Published: Aug 11, 2026Updated: Aug 17, 2026 Sources: CVE List NVDCWE-787
8.8HIGH
NVD MITRE
EPSS Score
0.6%
Top 55.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

Out-of-bounds write in Windows DNS allows an unauthorized attacker to execute code over an adjacent network.

In plain language

AI Act now

This is a serious flaw in Windows DNS Server that could let an attacker remotely run code if they can reach your DNS service; most small businesses should act quickly to patch if you run Windows DNS.

Executive summary

CVE-2026-62817 is a Windows DNS Server remote code execution vulnerability caused by an out-of-bounds write (CWE-787), where a remote attacker can trigger memory corruption over an adjacent network connection.

If affected, business impact
Full server takeoverWidespread network compromiseService outage and downtimeCredential theft and persistence

What to do now

  1. Check whether any device in your business runs the Windows DNS Server role (it can be a domain controller or a dedicated DNS server).
  2. Verify your Windows version/build and current patch level against the fixed versions listed below.
  3. Upgrade/patch Windows to the fixed version for your exact OS (listed in the next section) and reboot if required.
  4. If you cannot patch immediately, restrict network access to the DNS server (limit who can reach it) and monitor for unusual DNS-related traffic and crashes.
Usually a quick update

CVSS Vector Breakdown

AV:AAC:LPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:AAttack Vector
Adjacent
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-787

Affected Products

Microsoft
commercial·US
Windows 10 Version 1809On-premOS
Operating Systems / windows
Windows 11 version 23H2On-premOS
Operating Systems / windows
Windows Server 2019 (Server Core installation)On-premOS
Operating Systems / windows
Windows Server 2022On-premOS
Operating Systems / windows
Windows Server 2025 (Server Core installation)On-premOS
Operating Systems / windows
and 18 more affected products View all →

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-62817?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62817
msrc.microsoft.com
News mentions
4

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