# CVE-2018-8276: Scripting Engine Security Feature Bypass Vulnerability

CVE-2018-8276 is fixed in 6 products on 1 platform, first by KB4338826, released July 10, 2018. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2018-8276
- Priority: Routine
- CVSS: 4.3 (Important)
- EPSS: 0.0577
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Jul 10, 2018
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2018-8276

## Description

<p>A security feature bypass vulnerability exists in the Microsoft Chakra scripting engine that allows Control Flow Guard (CFG) to be bypassed. By itself, the CFG bypass vulnerability does not allow arbitrary code execution. However, an attacker could use the CFG bypass vulnerability in conjunction with another vulnerability, such as a remote code execution vulnerability, to run arbitrary code on a target system.</p> <p>To exploit the CFG bypass vulnerability, a user must be logged on to the Microsoft Chakra scripting engine and running it. The user would then need to browse to a malicious website.</p> <p>The security update addresses the CFG bypass vulnerability by helping to ensure that the Microsoft Chakra scripting engine properly handles accessing memory.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1703 for 32-bit Systems | 15063.1209 | [KB4345419](https://patchblox.com/security/data/fix/microsoft/kb4345419.md) | Jul 16, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1703 for 32-bit Systems | 15063.1206 | [KB4338826](https://patchblox.com/security/data/fix/microsoft/kb4338826.md) | Jul 10, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1703 for x64-based Systems | 15063.1209 | [KB4345419](https://patchblox.com/security/data/fix/microsoft/kb4345419.md) | Jul 16, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1703 for x64-based Systems | 15063.1206 | [KB4338826](https://patchblox.com/security/data/fix/microsoft/kb4338826.md) | Jul 10, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1709 for 32-bit Systems | 16299.551 | [KB4345420](https://patchblox.com/security/data/fix/microsoft/kb4345420.md) | Jul 16, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1709 for 32-bit Systems | 16299.547 | [KB4338825](https://patchblox.com/security/data/fix/microsoft/kb4338825.md) | Jul 10, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1709 for x64-based Systems | 16299.551 | [KB4345420](https://patchblox.com/security/data/fix/microsoft/kb4345420.md) | Jul 16, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1709 for x64-based Systems | 16299.547 | [KB4338825](https://patchblox.com/security/data/fix/microsoft/kb4338825.md) | Jul 10, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for 32-bit Systems | 17134.167 | [KB4345421](https://patchblox.com/security/data/fix/microsoft/kb4345421.md) | Jul 16, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for 32-bit Systems | 17134.165 | [KB4338819](https://patchblox.com/security/data/fix/microsoft/kb4338819.md) | Jul 10, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for x64-based Systems | 17134.167 | [KB4345421](https://patchblox.com/security/data/fix/microsoft/kb4345421.md) | Jul 16, 2018 |
| Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for x64-based Systems | 17134.165 | [KB4338819](https://patchblox.com/security/data/fix/microsoft/kb4338819.md) | Jul 10, 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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