A security feature bypass vulnerability exists in Microsoft Edge as a result of how memory is accessed in code compiled by the Edge Just-In-Time (JIT) compiler that allows Arbitrary Code Guard (ACG) to be bypassed. By itself, this ACG bypass vulnerability does not allow arbitrary code execution. However, an attacker could use the ACG bypass vulnerability in conjunction with another vulnerability, such as a remote code execution vulnerability, to run arbitrary code on a target system.
To exploit the ACG bypass vulnerability, a user must be logged on and running an affected version of Microsoft Edge. The user would then need to browse to a malicious website.
The security update addresses the ACG bypass vulnerability by helping to ensure that Microsoft Edge properly handles accessing memory in code compiled by the Edge JIT compiler.
## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1703 for 32-bit Systems | 15063.540 | [KB4034674](https://patchblox.com/security/data/fix/microsoft/kb4034674.md) | Aug 8, 2017 | | Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1703 for x64-based Systems | 15063.540 | [KB4034674](https://patchblox.com/security/data/fix/microsoft/kb4034674.md) | Aug 8, 2017 | --- 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo