CVE-2026-20934 Details
Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.
A race condition vulnerability has been identified in Windows SMB Server, allowing an authorized attacker to elevate privileges over the network. This issue arises from concurrent execution using shared resources without proper synchronization.
Users can download the security update for this vulnerability via the Microsoft Update Catalog. Security update KB5073724 is available for various Windows 10 versions, while KB5073722 can be downloaded for Windows Server 2016. Windows Server 2022 users should look for KB5073457, and those on Windows Server 2019 can download KB5073723. For Windows 11, security update KB5074109 is available for both ARM64 and x64-based systems. Windows Server 2025 users can download KB5073379.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jan 14, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20934 | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-362 | Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| microsoft windows 10 1607 | < 10.0.14393.8783 |
CPE
Remediation
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| microsoft windows 10 1809 | < 10.0.17763.8276 |
CPE
Remediation
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| microsoft windows 10 21h2 | < 10.0.19044.6809 |
CPE
Remediation
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| microsoft windows 10 22h2 | < 10.0.19045.6809 |
CPE
Remediation
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| microsoft windows 11 23h2 | < 10.0.22631.6491 |
CPE
Remediation
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| microsoft windows 11 24h2 | < 10.0.26100.7623 |
CPE
Remediation
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| microsoft windows 11 25h2 | < 10.0.26200.7623 |
CPE
Remediation
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| microsoft windows server 2012 | r2 |
CPE
Remediation
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| microsoft windows server 2016 | < 10.0.14393.8783 |
CPE
Remediation
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| microsoft windows server 2019 | < 10.0.17763.8276 |
CPE
Remediation
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| microsoft windows server 2022 | < 10.0.20348.4648 |
CPE
Remediation
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| microsoft windows server 2022 23h2 | < 10.0.25398.2092 |
CPE
Remediation
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| microsoft windows server 2025 | < 10.0.26100.32230 |
CPE
Remediation
| |
Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 30, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jan 16, 2026 | Initial Analysis | [email protected] |
| Jan 13, 2026 | New CVE Received | [email protected] |