An elevation of privilege vulnerability exists when Microsoft Edge does not properly validate JavaScript under specific conditions, potentially allowing script to run with elevated privileges.
In a web-based attack scenario, an attacker could host a website in an attempt to exploit the vulnerability. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit the vulnerability. However, in all cases an attacker would have no way to force a user to view the attacker-controlled content. Instead, an attacker would have to convince a user to take action. For example, an attacker could trick a user into clicking a link that takes the user to the attacker's site. An attacker who successfully exploited the vulnerability could elevate privileges in affected versions of Microsoft Edge. An attacker could then leverage these privileges with another vulnerability to run arbitrary code with medium integrity level privileges (permissions of the current user).
The security update addresses the vulnerability by correcting how Microsoft Edge validates and sanitizes JavaScript parameters.
## 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 2026-11-07T12:40:37Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo