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Privacy Statement Third-Party Cookies AcceptRejectManage cookies MSRC  Customer Guidance  Security Update Guide  Vulnerabilities  CVE-2026-49160 HTTP.sys Denial of Service Vulnerability New On this page  CVE-2026-49160  Subscribe RSS PowerShell  API  CSAF Security Vulnerability Released: Jun 9, 2026 Assigning CNA Microsoft CVE.org link CVE-2026-49160  Impact Denial of Service Max Severity Important Weakness CWE-400: Uncontrolled Resource Consumption CVSS Source Microsoft Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C Metrics CVSS:3.1 7.5 / 6.5  Base score metrics: 7.5 / Temporal score metrics: 6.5  Expand all  Collapse all Metric Value   Base score metrics(8) Attack Vector Network Attack Complexity Low Privileges Required None User Interaction None Scope Unchanged Confidentiality None Integrity None 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 Uncontrolled resource consumption in HTTP/2 allows an unauthorized attacker to deny service over a network. Exploitability The following table provides an exploitability assessment for this vulnerability at the time of original publication. Publicly disclosed Yes Exploited No Exploitability assessment Exploitation More Likely FAQ What actions should I take to help protect my devices from this vulnerability? Install the June 2026 Windows security updates listed in the Security Updates table. These updates enable the protections Microsoft released for this CVE. As part of these updates, Microsoft also introduced a new MaxHeadersCount registry setting. This setting allows you to limit the number of headers included in HTTP/2 and HTTP/3 requests that are accepted by the HTTP server. For more information, see KB5102602. Acknowledgements Quang Luong of Calif.io in collaboration with Codex with Calif.io https://www.calif.io/ 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: Jun 9, 2026 Windows 11 Version 23H2 for x64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 11 Version 23H2 for x64-based Systems, Content:, 1 link 5093998  Title: Download Security Update for Windows 11 Version 23H2 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.22631.7219 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 11 Version 23H2 for ARM64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 11 Version 23H2 for ARM64-based Systems, Content:, 1 link 5093998  Title: Download Security Update for Windows 11 Version 23H2 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.22631.7219 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 11 Version 25H2 for x64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 11 Version 25H2 for x64-based Systems, Content:, 1 link 5094126  Title: Download Security Update for Windows 11 Version 25H2 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26200.8655 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 11 Version 25H2 for ARM64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 11 Version 25H2 for ARM64-based Systems, Content:, 1 link 5094126  Title: Download Security Update for Windows 11 Version 25H2 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26200.8655 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 10 Version 22H2 for 32-bit Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 10 Version 22H2 for 32-bit Systems, Content:, 1 link 5094127  Title: Download Security Update for Windows 10 Version 22H2 for 32-bit Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19045.7417 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows Server 2025 (Server Core installation) - Denial of Service Important Title: Knowledge Base Articles for Windows Server 2025 (Server Core installation), Content:, 1 link 5094125  Title: Download Security Update for Windows Server 2025 (Server Core installation), Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.26100.32995 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 10 Version 22H2 for ARM64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 10 Version 22H2 for ARM64-based Systems, Content:, 1 link 5094127  Title: Download Security Update for Windows 10 Version 22H2 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19045.7417 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 10 Version 22H2 for x64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 10 Version 22H2 for x64-based Systems, Content:, 1 link 5094127  Title: Download Security Update for Windows 10 Version 22H2 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19045.7417 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows Server 2022 (Server Core installation) - Denial of Service Important Title: Knowledge Base Articles for Windows Server 2022 (Server Core installation), Content:, 1 link 5094128  Title: Download Security Update for Windows Server 2022 (Server Core installation), Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.20348.5256 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 10 Version 21H2 for x64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 10 Version 21H2 for x64-based Systems, Content:, 1 link 5094127  Title: Download Security Update for Windows 10 Version 21H2 for x64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19044.7417 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 10 Version 21H2 for ARM64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 10 Version 21H2 for ARM64-based Systems, Content:, 1 link 5094127  Title: Download Security Update for Windows 10 Version 21H2 for ARM64-based Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19044.7417 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 10 Version 21H2 for 32-bit Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 10 Version 21H2 for 32-bit Systems, Content:, 1 link 5094127  Title: Download Security Update for Windows 10 Version 21H2 for 32-bit Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.19044.7417 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 10 Version 1809 for 32-bit Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 10 Version 1809 for 32-bit Systems, Content:, 1 link 5094123  Title: Download Security Update for Windows 10 Version 1809 for 32-bit Systems, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.17763.8880 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows Server 2019 (Server Core installation) - Denial of Service Important Title: Knowledge Base Articles for Windows Server 2019 (Server Core installation), Content:, 1 link 5094123  Title: Download Security Update for Windows Server 2019 (Server Core installation), Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.17763.8880 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows Server 2019 - Denial of Service Important Title: Knowledge Base Articles for Windows Server 2019, Content:, 1 link 5094123  Title: Download Security Update for Windows Server 2019, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.17763.8880 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows Server 2022 - Denial of Service Important Title: Knowledge Base Articles for Windows Server 2022, Content:, 1 link 5094128  Title: Download Security Update for Windows Server 2022, Content:, 1 link Security Update  Title: Build numbers, Content: 10.0.20348.5256 Title: Assigning CNA, Content: Microsoft Title: Release date, Content: Jun 9, 2026 Windows 10 Version 1809 for x64-based Systems - Denial of Service Important Title: Knowledge Base Articles for Windows 10 Version 1809 for x64-based Systems, Content:, 1 link 5094123  Title: Download Security Update for Windows 10 Version 1809 for x64-based