# KB5123303: August 2026 security update

KB5123303, released August 11, 2026, fixes 3 CVEs across 2 products. None of them is reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/fix/microsoft/kb5123303
- Platform: Microsoft
- Released: Aug 11, 2026
- Priority: Urgent (Closes CVE-2026-66799, rated Critical)
- CVEs: 3, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/5123303

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Windows Server 2022](https://patchblox.com/security/data/product/microsoft/windows-server-2022.md) |  |  |
| [Windows Server 2022 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2022-server-core-installation.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-66799](https://patchblox.com/security/data/cve/CVE-2026-66799.md) | Urgent | Windows Key Guard | 7.8 | 0.0033 |  |
| [CVE-2026-6726](https://patchblox.com/security/data/cve/CVE-2026-6726.md) | High | Windows TPM | 7.9 | 0.0019 |  |
| [CVE-2026-6727](https://patchblox.com/security/data/cve/CVE-2026-6727.md) | Routine | Windows TPM | 5.9 | 0.0015 |  |

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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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo