CVE-2026-49801 Details
Description
Use of uninitialized resource in Windows SMB allows an authorized attacker to disclose information locally.
A vulnerability exists in Windows Server 2022, Windows Server 2019 (Server Core installation), Windows Server 2019, Windows 10 (all versions) and Windows 11 (all versions) that allows an authorized attacker to locally disclose information. This issue arises from the use of uninitialized resources in the Windows Server Message Block (SMB) protocol.
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 KB5099539, KB5099538, KB5099444, KB5099445, KB5101650, KB5095051, and KB5099540.
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 14, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49801 | [email protected] | PatchVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-908 | Use of Uninitialized Resource | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| microsoft windows 10 1607 | < 10.0.14393.9339 |
CPE
Remediation
| |
| 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 < 10.0.28000.2525 |
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
| |
| 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
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 22, 2026 | CVE Modified | [email protected] |
| Jul 16, 2026 | Initial Analysis | [email protected] |
| Jul 14, 2026 | CVE Modified | CISA-ADP |
| Jul 14, 2026 | New CVE Received | [email protected] |