# KB5087541: May 2026 cumulative update for Windows Server 23H2 KB5087541, released May 12, 2026, fixes 58 CVEs in Windows Server 2022, 23H2 Edition (Server Core installation) (build 25398.2330). None of them is reported as exploited. Patch Radar priority: Urgent. The product is no longer supported. - Web page: https://patchblox.com/security/fix/microsoft/kb5087541 - Platform: Microsoft - Released: May 12, 2026 - Priority: Urgent (Closes CVE-2026-41089, rated Critical) - CVEs: 58, exploited: 0, on CISA KEV: 0 - Vendor advisory: https://support.microsoft.com/help/5087541 ## Applies to | Product | Release | Fixed in | |---|---|---| | [Windows Server 2022, 23H2 Edition (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2022-23h2-edition-server-core-installation.md) | | 25398.2330 | ## CVEs this fix closes | CVE | Priority | Component | CVSS | EPSS | Exploitation | |---|---|---|---:|---:|---| | [CVE-2026-41089](https://patchblox.com/security/data/cve/CVE-2026-41089.md) | Urgent | Windows Netlogon | 9.8 | 0.7962 | | | [CVE-2026-41096](https://patchblox.com/security/data/cve/CVE-2026-41096.md) | Urgent | Microsoft Windows DNS | 9.8 | 0.0270 | | | [CVE-2026-40398](https://patchblox.com/security/data/cve/CVE-2026-40398.md) | Urgent | Windows Remote Desktop | 7.8 | 0.0267 | More likely | | [CVE-2026-33835](https://patchblox.com/security/data/cve/CVE-2026-33835.md) | Urgent | Windows Cloud Files Mini Filter Driver | 7.8 | 0.0212 | More likely | | [CVE-2026-33837](https://patchblox.com/security/data/cve/CVE-2026-33837.md) | Urgent | Windows TCP/IP | 7.8 | 0.0184 | More likely | | [CVE-2026-35416](https://patchblox.com/security/data/cve/CVE-2026-35416.md) | Urgent | Windows Ancillary Function Driver for WinSock | 7.0 | 0.0165 | More likely | | [CVE-2026-35421](https://patchblox.com/security/data/cve/CVE-2026-35421.md) | Urgent | Windows GDI | 7.8 | 0.0053 | | | [CVE-2026-40403](https://patchblox.com/security/data/cve/CVE-2026-40403.md) | Urgent | Windows Win32K - GRFX | 8.8 | 0.0043 | | | [CVE-2026-35417](https://patchblox.com/security/data/cve/CVE-2026-35417.md) | Urgent | Windows Win32K - ICOMP | 7.8 | 0.0035 | More likely | | [CVE-2026-33841](https://patchblox.com/security/data/cve/CVE-2026-33841.md) | Urgent | Windows Kernel | 7.8 | 0.0031 | More likely | | [CVE-2026-32161](https://patchblox.com/security/data/cve/CVE-2026-32161.md) | Urgent | Windows Native WiFi Miniport Driver | 7.5 | 0.0030 | | | [CVE-2026-40397](https://patchblox.com/security/data/cve/CVE-2026-40397.md) | Urgent | Windows Common Log File System Driver | 7.8 | 0.0027 | More likely | | [CVE-2026-35424](https://patchblox.com/security/data/cve/CVE-2026-35424.md) | High | Windows Internet Key Exchange (IKE) Protocol | 7.5 | 0.0119 | | | [CVE-2026-40406](https://patchblox.com/security/data/cve/CVE-2026-40406.md) | High | Windows TCP/IP | 7.5 | 0.0093 | | | [CVE-2026-40415](https://patchblox.com/security/data/cve/CVE-2026-40415.md) | High | Windows TCP/IP | 8.1 | 0.0079 | | | [CVE-2026-40414](https://patchblox.com/security/data/cve/CVE-2026-40414.md) | High | Windows TCP/IP | 7.4 | 0.0053 | | | [CVE-2026-34329](https://patchblox.com/security/data/cve/CVE-2026-34329.md) | High | Windows Message Queuing | 8.8 | 0.0046 | | | [CVE-2026-40413](https://patchblox.com/security/data/cve/CVE-2026-40413.md) | High | Windows TCP/IP | 7.4 | 0.0040 | | | [CVE-2026-33838](https://patchblox.com/security/data/cve/CVE-2026-33838.md) | High | Windows Message Queuing | 7.8 | 0.0040 | | | [CVE-2026-35415](https://patchblox.com/security/data/cve/CVE-2026-35415.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0033 | | | [CVE-2026-41095](https://patchblox.com/security/data/cve/CVE-2026-41095.md) | High | Data Deduplication | 7.8 | 0.0033 | | | [CVE-2026-40401](https://patchblox.com/security/data/cve/CVE-2026-40401.md) | High | Windows TCP/IP | 7.1 | 0.0033 | | | [CVE-2026-40399](https://patchblox.com/security/data/cve/CVE-2026-40399.md) | High | Windows TCP/IP | 7.8 | 0.0033 | | | [CVE-2026-34343](https://patchblox.com/security/data/cve/CVE-2026-34343.md) | High | Windows Application Identity (AppID) Subsystem | 7.8 | 0.0033 | | | [CVE-2026-35420](https://patchblox.com/security/data/cve/CVE-2026-35420.md) | High | Windows Kernel | 7.8 | 0.0032 | | | [CVE-2026-41088](https://patchblox.com/security/data/cve/CVE-2026-41088.md) | High | Windows Ancillary Function Driver for WinSock | 7.8 | 0.0032 | | | [CVE-2026-34344](https://patchblox.com/security/data/cve/CVE-2026-34344.md) | High | Windows Ancillary Function Driver for WinSock | 7.8 | 0.0031 | | | [CVE-2026-34330](https://patchblox.com/security/data/cve/CVE-2026-34330.md) | High | Windows Win32K - GRFX | 7.8 | 0.0030 | | | [CVE-2026-40377](https://patchblox.com/security/data/cve/CVE-2026-40377.md) | High | Windows Cryptographic Services | 7.8 | 0.0030 | | | [CVE-2026-40407](https://patchblox.com/security/data/cve/CVE-2026-40407.md) | High | Windows Common Log File System Driver | 7.8 | 0.0030 | | | [CVE-2026-34333](https://patchblox.com/security/data/cve/CVE-2026-34333.md) | High | Windows Win32K - GRFX | 7.8 | 0.0030 | | | [CVE-2026-40408](https://patchblox.com/security/data/cve/CVE-2026-40408.md) | High | Windows Kernel-Mode Drivers | 7.8 | 0.0030 | | | [CVE-2026-34342](https://patchblox.com/security/data/cve/CVE-2026-34342.md) | High | Windows Print Spooler Components | 7.0 | 0.0029 | | | [CVE-2025-54518](https://patchblox.com/security/data/cve/CVE-2025-54518.md) | High | AMD CPU Branch | 7.8 | 0.0029 | | | [CVE-2026-33834](https://patchblox.com/security/data/cve/CVE-2026-33834.md) | High | Windows Event Logging Service | 7.8 | 0.0027 | | | [CVE-2026-34347](https://patchblox.com/security/data/cve/CVE-2026-34347.md) | High | Windows Win32K - GRFX | 7.0 | 0.0026 | | | [CVE-2026-34338](https://patchblox.com/security/data/cve/CVE-2026-34338.md) | High | Windows Telephony Service | 7.8 | 0.0025 | | | [CVE-2026-40382](https://patchblox.com/security/data/cve/CVE-2026-40382.md) | High | Windows Telephony Service | 7.8 | 0.0025 | | | [CVE-2026-34336](https://patchblox.com/security/data/cve/CVE-2026-34336.md) | High | Windows DWM Core Library | 7.8 | 0.0025 | | | [CVE-2026-40410](https://patchblox.com/security/data/cve/CVE-2026-40410.md) | High | Windows SMB Client | 7.0 | 0.0024 | | | [CVE-2026-42825](https://patchblox.com/security/data/cve/CVE-2026-42825.md) | High | Windows Telephony Service | 7.0 | 0.0023 | | | [CVE-2026-34340](https://patchblox.com/security/data/cve/CVE-2026-34340.md) | High | Windows Projected File System | 7.0 | 0.0021 | | | [CVE-2026-34351](https://patchblox.com/security/data/cve/CVE-2026-34351.md) | High | Windows TCP/IP | 7.8 | 0.0021 | | | [CVE-2026-34345](https://patchblox.com/security/data/cve/CVE-2026-34345.md) | High | Windows Ancillary Function Driver for WinSock | 7.0 | 0.0020 | | | [CVE-2026-35418](https://patchblox.com/security/data/cve/CVE-2026-35418.md) | High | Windows Cloud Files Mini Filter Driver | 7.8 | 0.0020 | | | [CVE-2026-34341](https://patchblox.com/security/data/cve/CVE-2026-34341.md) | High | Windows Link-Layer Discovery Protocol (LLDP) | 7.0 | 0.0020 | | | [CVE-2026-33839](https://patchblox.com/security/data/cve/CVE-2026-33839.md) | High | Windows Win32K - GRFX | 7.0 | 0.0019 | | | [CVE-2026-34331](https://patchblox.com/security/data/cve/CVE-2026-34331.md) | High | Windows Win32K - GRFX | 7.0 | 0.0019 | | | [CVE-2026-34337](https://patchblox.com/security/data/cve/CVE-2026-34337.md) | High | Windows Cloud Files Mini Filter Driver | 7.8 | 0.0016 | | | [CVE-2026-34334](https://patchblox.com/security/data/cve/CVE-2026-34334.md) | High | Windows TCP/IP | 7.8 | 0.0015 | | | [CVE-2026-41097](https://patchblox.com/security/data/cve/CVE-2026-41097.md) | Routine | Windows Secure Boot | 6.7 | 0.0142 | | | [CVE-2026-35423](https://patchblox.com/security/data/cve/CVE-2026-35423.md) | Routine | Telnet Client | 5.4 | 0.0075 | | | [CVE-2026-35422](https://patchblox.com/security/data/cve/CVE-2026-35422.md) | Routine | Windows TCP/IP | 6.5 | 0.0061 | | | [CVE-2026-40380](https://patchblox.com/security/data/cve/CVE-2026-40380.md) | Routine | Windows Volume Manager Extension Driver | 6.2 | 0.0046 | | | [CVE-2026-21530](https://patchblox.com/security/data/cve/CVE-2026-21530.md) | Routine | Windows Rich Text Edit | 6.7 | 0.0032 | | | [CVE-2026-32170](https://patchblox.com/security/data/cve/CVE-2026-32170.md) | Routine | Windows Rich Text Edit Control | 6.7 | 0.0032 | | | [CVE-2026-34339](https://patchblox.com/security/data/cve/CVE-2026-34339.md) | Routine | Windows LDAP - Lightweight Directory Access Protocol | 5.5 | 0.0029 | | | [CVE-2026-32209](https://patchblox.com/security/data/cve/CVE-2026-32209.md) | Routine | Windows Filtering Platform (WFP) | 4.4 | 0.0020 | | --- Data as of 2026-11-07T12:40:37Z 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 Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.