# KB5075899: February 2026 cumulative update for Windows Server 2025 KB5075899, released February 10, 2026, fixes 29 CVEs across 2 products. 5 of them are being exploited (CVE-2026-21510); 5 on CISA KEV. Patch Radar priority: Patch now. - Web page: https://patchblox.com/security/fix/microsoft/kb5075899 - Platform: Microsoft - Released: Feb 10, 2026 - Priority: Patch now (Closes CVE-2026-21510, exploited (CISA KEV)) - CVEs: 29, exploited: 5, on CISA KEV: 5 - Vendor advisory: https://support.microsoft.com/help/5075899 ## Applies to | Product | Release | Fixed in | |---|---|---| | [Windows Server 2025](https://patchblox.com/security/data/product/microsoft/windows-server-2025.md) | | 26100.32370 | | [Windows Server 2025 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2025-server-core-installation.md) | | 26100.32370 | ## CVEs this fix closes | CVE | Priority | Component | CVSS | EPSS | Exploitation | |---|---|---|---:|---:|---| | [CVE-2026-21510](https://patchblox.com/security/data/cve/CVE-2026-21510.md) | Patch now | Windows Shell | 8.8 | 0.6124 | CISA KEV, Disclosed | | [CVE-2026-21513](https://patchblox.com/security/data/cve/CVE-2026-21513.md) | Patch now | MSHTML Framework | 8.8 | 0.1585 | CISA KEV, Disclosed | | [CVE-2026-21525](https://patchblox.com/security/data/cve/CVE-2026-21525.md) | Patch now | Windows Remote Access Connection Manager | 6.2 | 0.0504 | CISA KEV | | [CVE-2026-21533](https://patchblox.com/security/data/cve/CVE-2026-21533.md) | Patch now | Windows Remote Desktop | 7.8 | 0.0434 | CISA KEV | | [CVE-2026-21519](https://patchblox.com/security/data/cve/CVE-2026-21519.md) | Patch now | Desktop Window Manager | 7.8 | 0.0257 | CISA KEV | | [CVE-2026-21238](https://patchblox.com/security/data/cve/CVE-2026-21238.md) | Urgent | Windows Ancillary Function Driver for WinSock | 7.8 | 0.0333 | More likely | | [CVE-2026-21241](https://patchblox.com/security/data/cve/CVE-2026-21241.md) | Urgent | Windows Ancillary Function Driver for WinSock | 7.0 | 0.0256 | More likely | | [CVE-2026-21231](https://patchblox.com/security/data/cve/CVE-2026-21231.md) | Urgent | Windows Kernel | 7.8 | 0.0252 | More likely | | [CVE-2026-21253](https://patchblox.com/security/data/cve/CVE-2026-21253.md) | Urgent | Mailslot File System | 7.0 | 0.0079 | More likely | | [CVE-2026-20846](https://patchblox.com/security/data/cve/CVE-2026-20846.md) | High | Windows GDI+ | 7.5 | 0.0141 | | | [CVE-2026-21243](https://patchblox.com/security/data/cve/CVE-2026-21243.md) | High | Windows LDAP - Lightweight Directory Access Protocol | 7.5 | 0.0141 | | | [CVE-2026-21244](https://patchblox.com/security/data/cve/CVE-2026-21244.md) | High | Role: Windows Hyper-V | 7.3 | 0.0131 | | | [CVE-2026-21248](https://patchblox.com/security/data/cve/CVE-2026-21248.md) | High | Role: Windows Hyper-V | 7.3 | 0.0131 | | | [CVE-2026-21250](https://patchblox.com/security/data/cve/CVE-2026-21250.md) | High | Windows HTTP.sys | 7.8 | 0.0109 | | | [CVE-2026-21247](https://patchblox.com/security/data/cve/CVE-2026-21247.md) | High | Role: Windows Hyper-V | 7.3 | 0.0058 | | | [CVE-2026-21508](https://patchblox.com/security/data/cve/CVE-2026-21508.md) | High | Windows Storage | 7.0 | 0.0044 | | | [CVE-2026-21232](https://patchblox.com/security/data/cve/CVE-2026-21232.md) | High | Windows HTTP.sys | 7.8 | 0.0044 | | | [CVE-2026-21236](https://patchblox.com/security/data/cve/CVE-2026-21236.md) | High | Windows Ancillary Function Driver for WinSock | 7.8 | 0.0044 | | | [CVE-2026-21239](https://patchblox.com/security/data/cve/CVE-2026-21239.md) | High | Windows Kernel | 7.8 | 0.0044 | | | [CVE-2026-21245](https://patchblox.com/security/data/cve/CVE-2026-21245.md) | High | Windows Kernel | 7.8 | 0.0044 | | | [CVE-2026-21246](https://patchblox.com/security/data/cve/CVE-2026-21246.md) | High | Microsoft Graphics Component | 7.8 | 0.0044 | | | [CVE-2026-21251](https://patchblox.com/security/data/cve/CVE-2026-21251.md) | High | Windows Cluster Client Failover | 7.8 | 0.0044 | | | [CVE-2026-21255](https://patchblox.com/security/data/cve/CVE-2026-21255.md) | High | Role: Windows Hyper-V | 8.8 | 0.0038 | | | [CVE-2026-21242](https://patchblox.com/security/data/cve/CVE-2026-21242.md) | High | Windows Subsystem for Linux | 7.0 | 0.0036 | | | [CVE-2026-21240](https://patchblox.com/security/data/cve/CVE-2026-21240.md) | High | Windows HTTP.sys | 7.8 | 0.0028 | | | [CVE-2026-21234](https://patchblox.com/security/data/cve/CVE-2026-21234.md) | High | Windows Connected Devices Platform Service | 7.0 | 0.0027 | | | [CVE-2026-21237](https://patchblox.com/security/data/cve/CVE-2026-21237.md) | High | Windows Subsystem for Linux | 7.0 | 0.0027 | | | [CVE-2026-21249](https://patchblox.com/security/data/cve/CVE-2026-21249.md) | Routine | Windows NTLM | 3.3 | 0.1128 | | | [CVE-2026-21222](https://patchblox.com/security/data/cve/CVE-2026-21222.md) | Routine | Windows Kernel | 5.5 | 0.0060 | | --- Data as of 2026-11-07T06:34:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo