Summary
Impact: Remote Code Execution. Microsoft rating: Critical. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation of this vulnerability requires an attacker to win a race condition.
How could an attacker exploit this vulnerability?
An unauthenticated attacker could exploit this vulnerability by sending a specially crafted packet to an affected service over the network. Successful exploitation could allow the attacker to execute code on the target system. No authentication or user interaction is required.
Security updates
10.0.17763.9121 — https://support.microsoft.com/help/5120238
10.0.20348.5499 — https://support.microsoft.com/help/5120242
10.0.20348.5440 — https://support.microsoft.com/help/5120229
10.0.26100.33296 — https://support.microsoft.com/help/5120233
10.0.26100.33222 — https://support.microsoft.com/help/5120228
10.0.14393.9418 — https://support.microsoft.com/help/5120418
Vulnerabilities 1
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High 8.1
Windows DNS Server Remote Code Execution Vulnerability
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows DNS allows an unauthorized attacker to execute code over a network.
Revision history
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#2
Updated software table to remove clients versions because this vulnerability only impacts Windows Servers. This is an informational change only.
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#1
Information published.
References
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CVE-2026-62820 Windows DNS Server Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62820
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss