# CVE-2026-62817: Windows DNS Server Remote Code Execution Vulnerability

CVE-2026-62817 is fixed in 6 products on 1 platform, first by KB5120238, released August 11, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-62817
- Priority: Urgent
- CVSS: 8.8 (Critical)
- EPSS: 0.0054
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Aug 11, 2026
- Weakness: Out-of-bounds Write
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62817

## Description

<p>Out-of-bounds write in Windows DNS allows an unauthorized attacker to execute code over an adjacent network.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Windows Server 2019 | 17763.9121 | [KB5120238](https://patchblox.com/security/data/fix/microsoft/kb5120238.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2019 (Server Core installation) | 17763.9121 | [KB5120238](https://patchblox.com/security/data/fix/microsoft/kb5120238.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2022 | 20348.5440 | [KB5120229](https://patchblox.com/security/data/fix/microsoft/kb5120229.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2022 | 20348.5499 | [KB5120242](https://patchblox.com/security/data/fix/microsoft/kb5120242.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2022 (Server Core installation) | 20348.5440 | [KB5120229](https://patchblox.com/security/data/fix/microsoft/kb5120229.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2022 (Server Core installation) | 20348.5499 | [KB5120242](https://patchblox.com/security/data/fix/microsoft/kb5120242.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2025 | 26100.33222 | [KB5120228](https://patchblox.com/security/data/fix/microsoft/kb5120228.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2025 | 26100.33296 | [KB5120233](https://patchblox.com/security/data/fix/microsoft/kb5120233.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2025 (Server Core installation) | 26100.33222 | [KB5120228](https://patchblox.com/security/data/fix/microsoft/kb5120228.md) | Aug 11, 2026 |
| Microsoft | Windows Server 2025 (Server Core installation) | 26100.33296 | [KB5120233](https://patchblox.com/security/data/fix/microsoft/kb5120233.md) | Aug 11, 2026 |

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Data as of 2026-11-08T06:59:42Z 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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