CVE-2026-40399 Details
Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows TCP/IP allows an authorized attacker to elevate privileges locally.
A stack-based buffer overflow vulnerability has been identified in the Windows TCP/IP stack. This vulnerability allows an authorized attacker to locally elevate privileges. The issue affects several different versions and ranges of Windows, including various releases of Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, and Windows Server 2022. The vulnerability arises from a buffer overflow in the TCP/IP stack, which can be exploited by an attacker with local access to the system.
Users can apply the security update for this vulnerability, which is available through the Microsoft Update Catalog. Specific update details can be found in the Microsoft Knowledge Base articles KB5087538, KB5087537, KB5089548, KB5087420, KB5087544, and KB5087545.
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 May 7, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40399 | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-121 | Stack-based Buffer Overflow | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| microsoft windows 10 1607 | < 10.0.14393.9140 |
CPE
Remediation
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| microsoft windows 10 1809 | < 10.0.17763.8755 |
CPE
Remediation
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| microsoft windows 10 21h2 | < 10.0.19044.7291 |
CPE
Remediation
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| microsoft windows 10 22h2 | < 10.0.19045.7291 |
CPE
Remediation
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| microsoft windows 11 23h2 | < 10.0.22631.7079 |
CPE
Remediation
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| microsoft windows 11 24h2 | < 10.0.26100.8390 |
CPE
Remediation
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| microsoft windows 11 25h2 | < 10.0.26200.8390 |
CPE
Remediation
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| microsoft windows 11 26h1 | < 10.0.28000.2113 |
CPE
Remediation
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| microsoft windows server 2016 | < 10.0.14393.9140 |
CPE
Remediation
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| microsoft windows server 2019 | < 10.0.17763.8755 |
CPE
Remediation
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| microsoft windows server 2022 | < 10.0.20348.5074 |
CPE
Remediation
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| microsoft windows server 2022 23h2 | < 10.0.25398.2330 |
CPE
Remediation
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| microsoft windows server 2025 | < 10.0.26100.32772 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 1, 2026 | CVE Modified | [email protected] |
| May 15, 2026 | Initial Analysis | [email protected] |
| May 12, 2026 | New CVE Received | [email protected] |