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Privacy Statement Third-Party Cookies AcceptRejectManage cookies MSRC  Customer Guidance  Security Update Guide  Vulnerabilities  CVE-2026-50407 Windows Resilient File System (ReFS) Elevation of Privilege Vulnerability New On this page  CVE-2026-50407  Subscribe RSS PowerShell  API  CSAF Security Vulnerability Released: Jul 14, 2026 Assigning CNA Microsoft CVE.org link CVE-2026-50407  Impact Elevation of Privilege Max Severity Important Weakness CWE-122: Heap-based Buffer Overflow CVSS Source Microsoft Vector String CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C Metrics CVSS:3.1 7.8 / 6.8  Base score metrics: 7.8 / Temporal score metrics: 6.8  Expand all  Collapse all Metric Value   Base score metrics(8) Attack Vector Local Attack Complexity Low Privileges Required Low User Interaction None Scope Unchanged Confidentiality High Integrity High Availability High   Temporal score metrics(3) Exploit Code Maturity Unproven Remediation Level Official Fix Report Confidence Confirmed Please see Common Vulnerability Scoring System for more information on the definition of these metrics. Executive Summary Heap-based buffer overflow in Windows Resilient File System (ReFS) allows an authorized attacker to elevate privileges locally. Exploitability The following table provides an exploitability assessment for this vulnerability at the time of original publication. Publicly disclosed No Exploited No Exploitability assessment Exploitation Less Likely Acknowledgements Thanatos Tian & wgg & @2st__ with Diffract pwn2addr Thunder_J 𝕏 @ thunderj17 yhw & txz Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgements for more information. Security Updates To determine the support lifecycle for your software, see the Microsoft Support Lifecycle. Release date Descending  Edit columns  Download  Filters  Product Family  Max Severity  Impact  Platform   Clear Release date  Product Platform Impact Max Severity Article Download Build Number Assigning CNA Title: Release date, Content: Jul 14, 2026 Windows Server 2016 (Server Core installation) - Elevation of Privilege Important Title: Knowledge Base Articles for Windows Server 2016 (Server Core installation), Content:, 1 link 5099535  Title: Download Security Update for Windows Server 2016 (Server Core installation), Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.14393.9339 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2016 - Elevation of Privilege Important Title: Knowledge Base Articles for Windows Server 2016, Content:, 1 link 5099535  Title: Download Security Update for Windows Server 2016, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.14393.9339 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 1607 for x64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 10 Version 1607 for x64-based Systems, Content:, 1 link 5099535  Title: Download Security Update for Windows 10 Version 1607 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.14393.9339 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 1607 for 32-bit Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 10 Version 1607 for 32-bit Systems, Content:, 1 link 5099535  Title: Download Security Update for Windows 10 Version 1607 for 32-bit Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.14393.9339 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 11 Version 26H1 for ARM64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 11 Version 26H1 for ARM64-based Systems, Content:, 1 link 5101649  Title: Download Security Update for Windows 11 Version 26H1 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.28000.2525 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 11 version 26H1 for x64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 11 version 26H1 for x64-based Systems, Content:, 1 link 5101649  Title: Download Security Update for Windows 11 version 26H1 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.28000.2525 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2025 - Elevation of Privilege Important Title: Knowledge Base Articles for Windows Server 2025, Content:, 1 link 5099536  Title: Download Security Update for Windows Server 2025, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26100.33158 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 11 Version 24H2 for x64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 11 Version 24H2 for x64-based Systems, Content:, 1 link 5101650  Title: Download Security Update for Windows 11 Version 24H2 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26100.8875 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 11 Version 24H2 for ARM64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 11 Version 24H2 for ARM64-based Systems, Content:, 1 link 5101650  Title: Download Security Update for Windows 11 Version 24H2 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26100.8875 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 11 Version 25H2 for x64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 11 Version 25H2 for x64-based Systems, Content:, 1 link 5101650  Title: Download Security Update for Windows 11 Version 25H2 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26200.8875 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 11 Version 25H2 for ARM64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 11 Version 25H2 for ARM64-based Systems, Content:, 1 link 5101650  Title: Download Security Update for Windows 11 Version 25H2 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26200.8875 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows Server 2025 (Server Core installation) - Elevation of Privilege Important Title: Knowledge Base Articles for Windows Server 2025 (Server Core installation), Content:, 1 link 5099536  Title: Download Security Update for Windows Server 2025 (Server Core installation), Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26100.33158 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 22H2 for 32-bit Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 10 Version 22H2 for 32-bit Systems, Content:, 1 link 5099539  Title: Download Security Update for Windows 10 Version 22H2 for 32-bit Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19045.7548 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 22H2 for ARM64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 10 Version 22H2 for ARM64-based Systems, Content:, 1 link 5099539  Title: Download Security Update for Windows 10 Version 22H2 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19045.7548 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 22H2 for x64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 10 Version 22H2 for x64-based Systems, Content:, 1 link 5099539  Title: Download Security Update for Windows 10 Version 22H2 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19045.7548 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 21H2 for x64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 10 Version 21H2 for x64-based Systems, Content:, 1 link 5099539  Title: Download Security Update for Windows 10 Version 21H2 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19044.7548 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 21H2 for ARM64-based Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 10 Version 21H2 for ARM64-based Systems, Content:, 1 link 5099539  Title: Download Security Update for Windows 10 Version 21H2 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19044.7548 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jul 14, 2026 Windows 10 Version 21H2 for 32-bit Systems - Elevation of Privilege Important Title: Knowledge Base Articles for Windows 10 Version 21H2 for 32-bit Systems, Conte