CVE-2026-56649 Details
Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Network File System allows an unauthorized attacker to execute code over a network.
A race condition vulnerability has been identified in the Windows Network File System, allowing an unauthorized attacker to execute code remotely over the network. This issue arises from improper synchronization in concurrent execution using shared resources.
Users can apply the security update KB5099535 for Windows Server 2016, Windows 10 Version 1607, and various other Windows 11 versions. For Windows Server 2022, the security update KB5099540 is available. Windows Server 2019 users can also apply the security update KB5099538. Instructions for downloading these security updates are available through the Microsoft Update Catalog.
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 Jul 10, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56649 | [email protected] | PatchVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-362 | Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') | [email protected] |
| CWE-416 | Use After Free | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| microsoft windows 10 1607 | < 10.0.14393.9339 |
CPE
Remediation
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| microsoft windows 10 1809 | < 10.0.17763.9020 |
CPE
Remediation
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| microsoft windows 10 21h2 | < 10.0.19044.7548 |
CPE
Remediation
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| microsoft windows 10 22h2 | < 10.0.19045.7548 |
CPE
Remediation
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| microsoft windows 11 24h2 | < 10.0.26100.8875 |
CPE
Remediation
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| microsoft windows 11 25h2 | < 10.0.26200.8875 |
CPE
Remediation
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| microsoft windows 11 26h1 | < 10.0.28000.2269 |
CPE
Remediation
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| microsoft windows server 2012 | r2 |
CPE
Remediation
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| microsoft windows server 2016 | < 10.0.14393.9339 |
CPE
Remediation
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| microsoft windows server 2019 | < 10.0.17763.9020 |
CPE
Remediation
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| microsoft windows server 2022 | < 10.0.20348.5386 |
CPE
Remediation
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| microsoft windows server 2025 | < 10.0.26100.33158 |
CPE
Remediation
| |
Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 22, 2026 | CVE Modified | [email protected] |
| Jul 17, 2026 | Initial Analysis | [email protected] |
| Jul 15, 2026 | CVE Modified | CISA-ADP |
| Jul 14, 2026 | CVE Modified | CISA-ADP |
| Jul 14, 2026 | New CVE Received | [email protected] |