# CVE-2018-8226: HTTP.sys Denial of Service Vulnerability

CVE-2018-8226 is fixed in 14 products on 1 platform, first by KB4284880, released June 12, 2018. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2018-8226
- Priority: Routine
- CVSS: 5.3 (Important)
- EPSS: 0.1439
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Unlikely
- Published: Jun 12, 2018
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2018-8226

## Description

<p>A denial of service vulnerability exists in the HTTP 2.0 protocol stack (HTTP.sys) when HTTP.sys improperly parses specially crafted HTTP 2.0 requests. An attacker who successfully exploited the vulnerability could create a denial of service condition, causing the target system to become unresponsive.</p> <p>To exploit this vulnerability, an attacker could send a specially crafted HTTP packet to a target system, causing the affected system to become nonresponsive.</p> <p>The update addresses the vulnerability by modifying how the Windows HTTP protocol stack handles HTTP 2.0 requests. Note that the denial of service vulnerability would not allow an attacker to execute code or to elevate user rights.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Windows 10 Version 1607 for 32-bit Systems | 14393.2312 | [KB4284880](https://patchblox.com/security/data/fix/microsoft/kb4284880.md) | Jun 12, 2018 |
| Microsoft | Windows 10 Version 1607 for x64-based Systems | 14393.2312 | [KB4284880](https://patchblox.com/security/data/fix/microsoft/kb4284880.md) | Jun 12, 2018 |
| Microsoft | Windows 10 Version 1703 for 32-bit Systems | 15063.1155 | [KB4284874](https://patchblox.com/security/data/fix/microsoft/kb4284874.md) | Jun 12, 2018 |
| Microsoft | Windows 10 Version 1703 for x64-based Systems | 15063.1155 | [KB4284874](https://patchblox.com/security/data/fix/microsoft/kb4284874.md) | Jun 12, 2018 |
| Microsoft | Windows 10 Version 1709 for 32-bit Systems | 16299.492 | [KB4284819](https://patchblox.com/security/data/fix/microsoft/kb4284819.md) | Jun 12, 2018 |
| Microsoft | Windows 10 Version 1709 for x64-based Systems | 16299.492 | [KB4284819](https://patchblox.com/security/data/fix/microsoft/kb4284819.md) | Jun 12, 2018 |
| Microsoft | Windows 10 Version 1803 for 32-bit Systems | 17134.112 | [KB4284835](https://patchblox.com/security/data/fix/microsoft/kb4284835.md) | Jun 12, 2018 |
| Microsoft | Windows 10 Version 1803 for x64-based Systems | 17134.112 | [KB4284835](https://patchblox.com/security/data/fix/microsoft/kb4284835.md) | Jun 12, 2018 |
| Microsoft | Windows 10 for 32-bit Systems | 10240.17889 | [KB4284860](https://patchblox.com/security/data/fix/microsoft/kb4284860.md) | Jun 12, 2018 |
| Microsoft | Windows 10 for x64-based Systems | 10240.17889 | [KB4284860](https://patchblox.com/security/data/fix/microsoft/kb4284860.md) | Jun 12, 2018 |
| Microsoft | Windows Server 2016 | 14393.2312 | [KB4284880](https://patchblox.com/security/data/fix/microsoft/kb4284880.md) | Jun 12, 2018 |
| Microsoft | Windows Server 2016 (Server Core installation) | 14393.2312 | [KB4284880](https://patchblox.com/security/data/fix/microsoft/kb4284880.md) | Jun 12, 2018 |
| Microsoft | Windows Server, version 1709  (Server Core Installation) | 16299.492 | [KB4284819](https://patchblox.com/security/data/fix/microsoft/kb4284819.md) | Jun 12, 2018 |
| Microsoft | Windows Server, version 1803  (Server Core Installation) | 17134.112 | [KB4284835](https://patchblox.com/security/data/fix/microsoft/kb4284835.md) | Jun 12, 2018 |

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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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