# KB5006739: October 2021 security update

KB5006739, released October 12, 2021, fixes 28 CVEs across 2 products. One of them is being exploited (CVE-2021-40449); 1 on CISA KEV. Patch Radar priority: Patch now.

- Web page: https://patchblox.com/security/fix/microsoft/kb5006739
- Platform: Microsoft
- Released: Oct 12, 2021
- Priority: Patch now (Closes CVE-2021-40449, exploited (CISA KEV, ransomware))
- CVEs: 28, exploited: 1, on CISA KEV: 1
- Vendor advisory: https://support.microsoft.com/help/5006739

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Windows Server 2012](https://patchblox.com/security/data/product/microsoft/windows-server-2012.md) |  |  |
| [Windows Server 2012 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2012-server-core-installation.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-40449](https://patchblox.com/security/data/cve/CVE-2021-40449.md) | Patch now | Windows Win32K | 7.8 | 0.8194 | CISA KEV, Ransomware |
| [CVE-2021-36970](https://patchblox.com/security/data/cve/CVE-2021-36970.md) | Urgent | Windows Print Spooler Components | 8.8 | 0.0306 | More likely |
| [CVE-2021-40443](https://patchblox.com/security/data/cve/CVE-2021-40443.md) | Urgent | Windows Common Log File System Driver | 7.8 | 0.0065 | More likely |
| [CVE-2021-40466](https://patchblox.com/security/data/cve/CVE-2021-40466.md) | Urgent | Windows Common Log File System Driver | 7.8 | 0.0065 | More likely |
| [CVE-2021-40467](https://patchblox.com/security/data/cve/CVE-2021-40467.md) | Urgent | Windows Common Log File System Driver | 7.8 | 0.0054 | More likely |
| [CVE-2021-40469](https://patchblox.com/security/data/cve/CVE-2021-40469.md) | High | Role: DNS Server | 7.2 | 0.0758 | Disclosed |
| [CVE-2021-36953](https://patchblox.com/security/data/cve/CVE-2021-36953.md) | High | Windows TCP/IP | 7.5 | 0.0505 |  |
| [CVE-2021-40463](https://patchblox.com/security/data/cve/CVE-2021-40463.md) | High | Windows Network Address Translation (NAT) | 7.7 | 0.0258 |  |
| [CVE-2021-40465](https://patchblox.com/security/data/cve/CVE-2021-40465.md) | High | Windows Text Shaping | 7.8 | 0.0247 |  |
| [CVE-2021-40476](https://patchblox.com/security/data/cve/CVE-2021-40476.md) | High | Windows AppContainer | 7.5 | 0.0240 |  |
| [CVE-2021-41331](https://patchblox.com/security/data/cve/CVE-2021-41331.md) | High | Microsoft Windows Codecs Library | 7.8 | 0.0203 |  |
| [CVE-2021-41340](https://patchblox.com/security/data/cve/CVE-2021-41340.md) | High | Microsoft Graphics Component | 7.8 | 0.0203 |  |
| [CVE-2021-41335](https://patchblox.com/security/data/cve/CVE-2021-41335.md) | High | Windows Kernel | 7.8 | 0.0137 | Disclosed |
| [CVE-2021-40488](https://patchblox.com/security/data/cve/CVE-2021-40488.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0100 |  |
| [CVE-2021-26441](https://patchblox.com/security/data/cve/CVE-2021-26441.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0094 |  |
| [CVE-2021-40478](https://patchblox.com/security/data/cve/CVE-2021-40478.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0084 |  |
| [CVE-2021-40489](https://patchblox.com/security/data/cve/CVE-2021-40489.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0084 |  |
| [CVE-2021-41345](https://patchblox.com/security/data/cve/CVE-2021-41345.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0083 |  |
| [CVE-2021-26442](https://patchblox.com/security/data/cve/CVE-2021-26442.md) | High | Windows HTTP.sys | 7.0 | 0.0079 |  |
| [CVE-2021-40477](https://patchblox.com/security/data/cve/CVE-2021-40477.md) | High | Windows Event Tracing | 7.8 | 0.0058 |  |
| [CVE-2021-41332](https://patchblox.com/security/data/cve/CVE-2021-41332.md) | Routine | Windows Print Spooler Components | 6.5 | 0.0272 |  |
| [CVE-2021-41342](https://patchblox.com/security/data/cve/CVE-2021-41342.md) | Routine | Windows MSHTML Platform | 6.8 | 0.0163 |  |
| [CVE-2021-40460](https://patchblox.com/security/data/cve/CVE-2021-40460.md) | Routine | Windows Remote Procedure Call Runtime | 6.5 | 0.0161 |  |
| [CVE-2021-38662](https://patchblox.com/security/data/cve/CVE-2021-38662.md) | Routine | Windows Fast FAT Driver | 5.5 | 0.0078 |  |
| [CVE-2021-38663](https://patchblox.com/security/data/cve/CVE-2021-38663.md) | Routine | Windows exFAT File System | 5.5 | 0.0073 |  |
| [CVE-2021-41343](https://patchblox.com/security/data/cve/CVE-2021-41343.md) | Routine | Windows Fast FAT Driver | 5.5 | 0.0073 |  |
| [CVE-2021-40455](https://patchblox.com/security/data/cve/CVE-2021-40455.md) | Routine | Windows Installer | 5.5 | 0.0056 |  |
| [CVE-2021-40454](https://patchblox.com/security/data/cve/CVE-2021-40454.md) | Routine | Rich Text Edit Control | 5.5 | 0.0050 |  |

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Data as of 2026-11-07T18:46:35Z 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

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