# KB5004245: July 2021 cumulative update for Windows 10 1909

KB5004245, released July 13, 2021, fixes 66 CVEs across 4 products. 3 of them are being exploited (CVE-2021-34448); 3 on CISA KEV. Patch Radar priority: Patch now. The product is no longer supported.

- Web page: https://patchblox.com/security/fix/microsoft/kb5004245
- Platform: Microsoft
- Released: Jul 13, 2021
- Priority: Patch now (Closes CVE-2021-34448, exploited (CISA KEV))
- CVEs: 66, exploited: 3, on CISA KEV: 3
- Vendor advisory: https://support.microsoft.com/help/5004245

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Windows 10 Version 1909 for 32-bit Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-1909-for-32-bit-systems.md) |  | 18363.1679 |
| [Windows 10 Version 1909 for ARM64-based Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-1909-for-arm64-based-systems.md) |  | 18363.1679 |
| [Windows 10 Version 1909 for x64-based Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-1909-for-x64-based-systems.md) |  | 18363.1679 |
| [Windows Server, version 1909 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-version-1909-server-core-installation.md) |  | 18363.1679 |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-34448](https://patchblox.com/security/data/cve/CVE-2021-34448.md) | Patch now | Microsoft Scripting Engine | 6.8 | 0.4006 | CISA KEV |
| [CVE-2021-33771](https://patchblox.com/security/data/cve/CVE-2021-33771.md) | Patch now | Windows Kernel | 7.8 | 0.1017 | CISA KEV |
| [CVE-2021-31979](https://patchblox.com/security/data/cve/CVE-2021-31979.md) | Patch now | Windows Kernel | 7.8 | 0.0454 | CISA KEV |
| [CVE-2021-34449](https://patchblox.com/security/data/cve/CVE-2021-34449.md) | Urgent | Windows Win32K | 7.0 | 0.0271 | More likely |
| [CVE-2021-34450](https://patchblox.com/security/data/cve/CVE-2021-34450.md) | Urgent | Role: Windows Hyper-V | 8.5 | 0.0250 |  |
| [CVE-2021-34503](https://patchblox.com/security/data/cve/CVE-2021-34503.md) | Urgent | Microsoft Windows Media Foundation | 7.8 | 0.0231 |  |
| [CVE-2021-34497](https://patchblox.com/security/data/cve/CVE-2021-34497.md) | Urgent | Windows MSHTML Platform | 6.8 | 0.0215 |  |
| [CVE-2021-31183](https://patchblox.com/security/data/cve/CVE-2021-31183.md) | High | Windows TCP/IP | 7.5 | 0.0384 |  |
| [CVE-2021-34504](https://patchblox.com/security/data/cve/CVE-2021-34504.md) | High | Windows Address Book | 7.8 | 0.0347 |  |
| [CVE-2021-33788](https://patchblox.com/security/data/cve/CVE-2021-33788.md) | High | Windows Local Security Authority Subsystem Service (LSASS) | 7.5 | 0.0328 |  |
| [CVE-2021-34476](https://patchblox.com/security/data/cve/CVE-2021-34476.md) | High | Common Internet File System | 7.5 | 0.0328 |  |
| [CVE-2021-34490](https://patchblox.com/security/data/cve/CVE-2021-34490.md) | High | Windows TCP/IP | 7.5 | 0.0328 |  |
| [CVE-2021-33785](https://patchblox.com/security/data/cve/CVE-2021-33785.md) | High | Windows AF_UNIX Socket Provider | 7.5 | 0.0325 |  |
| [CVE-2021-34489](https://patchblox.com/security/data/cve/CVE-2021-34489.md) | High | Microsoft Graphics Component | 7.8 | 0.0247 |  |
| [CVE-2021-34492](https://patchblox.com/security/data/cve/CVE-2021-34492.md) | High | Windows PFX Encryption | 8.1 | 0.0247 | Disclosed |
| [CVE-2021-33749](https://patchblox.com/security/data/cve/CVE-2021-33749.md) | High | Role: DNS Server | 8.8 | 0.0242 |  |
| [CVE-2021-33750](https://patchblox.com/security/data/cve/CVE-2021-33750.md) | High | Role: DNS Server | 8.8 | 0.0242 |  |
| [CVE-2021-33752](https://patchblox.com/security/data/cve/CVE-2021-33752.md) | High | Role: DNS Server | 8.8 | 0.0242 |  |
| [CVE-2021-33781](https://patchblox.com/security/data/cve/CVE-2021-33781.md) | High | Windows Active Directory | 8.1 | 0.0241 | Disclosed |
| [CVE-2021-33756](https://patchblox.com/security/data/cve/CVE-2021-33756.md) | High | Role: DNS Server | 8.8 | 0.0241 |  |
| [CVE-2021-34521](https://patchblox.com/security/data/cve/CVE-2021-34521.md) | High | Microsoft Windows Codecs Library | 7.8 | 0.0238 |  |
| [CVE-2021-34508](https://patchblox.com/security/data/cve/CVE-2021-34508.md) | High | Windows Kernel | 8.8 | 0.0225 |  |
| [CVE-2021-34438](https://patchblox.com/security/data/cve/CVE-2021-34438.md) | High | Microsoft Graphics Component | 7.8 | 0.0222 |  |
| [CVE-2021-34441](https://patchblox.com/security/data/cve/CVE-2021-34441.md) | High | Microsoft Windows Media Foundation | 7.8 | 0.0222 |  |
| [CVE-2021-34446](https://patchblox.com/security/data/cve/CVE-2021-34446.md) | High | Windows HTML Platform | 8.0 | 0.0205 |  |
| [CVE-2021-34516](https://patchblox.com/security/data/cve/CVE-2021-34516.md) | High | Windows Win32K | 7.8 | 0.0130 |  |
| [CVE-2021-34498](https://patchblox.com/security/data/cve/CVE-2021-34498.md) | High | Microsoft Graphics Component | 7.8 | 0.0106 |  |
| [CVE-2021-34512](https://patchblox.com/security/data/cve/CVE-2021-34512.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0106 |  |
| [CVE-2021-34513](https://patchblox.com/security/data/cve/CVE-2021-34513.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0106 |  |
| [CVE-2021-34510](https://patchblox.com/security/data/cve/CVE-2021-34510.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0095 |  |
| [CVE-2021-34462](https://patchblox.com/security/data/cve/CVE-2021-34462.md) | High | Windows AppX Deployment Extensions | 7.0 | 0.0085 |  |
| [CVE-2021-33751](https://patchblox.com/security/data/cve/CVE-2021-33751.md) | High | Windows Storage Spaces Controller | 7.0 | 0.0082 |  |
| [CVE-2021-34514](https://patchblox.com/security/data/cve/CVE-2021-34514.md) | High | Windows Kernel | 7.8 | 0.0070 |  |
| [CVE-2021-33743](https://patchblox.com/security/data/cve/CVE-2021-33743.md) | High | Windows Projected File System | 7.8 | 0.0065 |  |
| [CVE-2021-33759](https://patchblox.com/security/data/cve/CVE-2021-33759.md) | High | Windows Desktop Bridge | 7.8 | 0.0065 |  |
| [CVE-2021-33784](https://patchblox.com/security/data/cve/CVE-2021-33784.md) | High | Windows Cloud Files Mini Filter Driver | 7.8 | 0.0065 |  |
| [CVE-2021-33773](https://patchblox.com/security/data/cve/CVE-2021-33773.md) | High | Windows Remote Access Connection Manager | 7.8 | 0.0064 |  |
| [CVE-2021-34445](https://patchblox.com/security/data/cve/CVE-2021-34445.md) | High | Windows Remote Access Connection Manager | 7.8 | 0.0064 |  |
| [CVE-2021-33774](https://patchblox.com/security/data/cve/CVE-2021-33774.md) | High | Windows Event Tracing | 7.0 | 0.0064 |  |
| [CVE-2021-33761](https://patchblox.com/security/data/cve/CVE-2021-33761.md) | High | Windows Remote Access Connection Manager | 7.8 | 0.0061 |  |
| [CVE-2021-34488](https://patchblox.com/security/data/cve/CVE-2021-34488.md) | High | Windows Console Driver | 7.8 | 0.0057 |  |
| [CVE-2021-34511](https://patchblox.com/security/data/cve/CVE-2021-34511.md) | High | Windows Installer | 7.8 | 0.0057 |  |
| [CVE-2021-34460](https://patchblox.com/security/data/cve/CVE-2021-34460.md) | High | Windows Storage Spaces Controller | 7.8 | 0.0056 |  |
| [CVE-2021-34456](https://patchblox.com/security/data/cve/CVE-2021-34456.md) | High | Windows Remote Access Connection Manager | 7.8 | 0.0056 |  |
| [CVE-2021-34455](https://patchblox.com/security/data/cve/CVE-2021-34455.md) | High | Windows File History Service | 7.8 | 0.0053 |  |
| [CVE-2021-34459](https://patchblox.com/security/data/cve/CVE-2021-34459.md) | High | Windows AppContainer | 7.8 | 0.0053 |  |
| [CVE-2021-34507](https://patchblox.com/security/data/cve/CVE-2021-34507.md) | Routine | Windows Remote Assistance | 6.5 | 0.0326 |  |
| [CVE-2021-33755](https://patchblox.com/security/data/cve/CVE-2021-33755.md) | Routine | Role: Windows Hyper-V | 6.3 | 0.0314 |  |
| [CVE-2021-33757](https://patchblox.com/security/data/cve/CVE-2021-33757.md) | Routine | Windows Security Account Manager | 5.3 | 0.0295 |  |
| [CVE-2021-33783](https://patchblox.com/security/data/cve/CVE-2021-33783.md) | Routine | Windows SMB | 6.5 | 0.0277 |  |
| [CVE-2021-34500](https://patchblox.com/security/data/cve/CVE-2021-34500.md) | Routine | Windows Kernel | 6.3 | 0.0266 |  |
| [CVE-2021-33782](https://patchblox.com/security/data/cve/CVE-2021-33782.md) | Routine | Windows Authenticode | 5.5 | 0.0225 |  |
| [CVE-2021-34447](https://patchblox.com/security/data/cve/CVE-2021-34447.md) | Routine | Windows MSHTML Platform | 6.8 | 0.0205 |  |
| [CVE-2021-34496](https://patchblox.com/security/data/cve/CVE-2021-34496.md) | Routine | Microsoft Graphics Component | 5.5 | 0.0204 |  |
| [CVE-2021-33760](https://patchblox.com/security/data/cve/CVE-2021-33760.md) | Routine | Microsoft Windows Codecs Library | 5.5 | 0.0098 |  |
| [CVE-2021-34491](https://patchblox.com/security/data/cve/CVE-2021-34491.md) | Routine | Windows Win32K | 5.5 | 0.0097 |  |
| [CVE-2021-34509](https://patchblox.com/security/data/cve/CVE-2021-34509.md) | Routine | Windows Storage Spaces Controller | 5.5 | 0.0095 |  |
| [CVE-2021-33763](https://patchblox.com/security/data/cve/CVE-2021-33763.md) | Routine | Windows Remote Access Connection Manager | 5.5 | 0.0088 |  |
| [CVE-2021-34440](https://patchblox.com/security/data/cve/CVE-2021-34440.md) | Routine | Microsoft Graphics Component | 5.5 | 0.0088 |  |
| [CVE-2021-34454](https://patchblox.com/security/data/cve/CVE-2021-34454.md) | Routine | Windows Shell | 5.5 | 0.0087 |  |
| [CVE-2021-34457](https://patchblox.com/security/data/cve/CVE-2021-34457.md) | Routine | Windows Remote Access Connection Manager | 5.5 | 0.0087 |  |
| [CVE-2021-31961](https://patchblox.com/security/data/cve/CVE-2021-31961.md) | Routine | Windows Installer | 6.1 | 0.0081 |  |
| [CVE-2021-34466](https://patchblox.com/security/data/cve/CVE-2021-34466.md) | Routine | Windows Hello | 5.7 | 0.0081 |  |
| [CVE-2021-33744](https://patchblox.com/security/data/cve/CVE-2021-33744.md) | Routine | Windows Secure Kernel Mode | 5.3 | 0.0079 |  |
| [CVE-2021-33765](https://patchblox.com/security/data/cve/CVE-2021-33765.md) | Routine | Windows Installer | 6.2 | 0.0073 |  |
| [CVE-2021-34493](https://patchblox.com/security/data/cve/CVE-2021-34493.md) | Routine | Windows Partition Management Driver | 6.7 | 0.0065 |  |

---

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