An information disclosure vulnerability exists when the Microsoft Edge Fetch API incorrectly handles a filtered response type. An attacker could use the vulnerability to read the URL of a cross-origin request. Websites that that do not securely populate the URL with confidential information could allow information to be disclosed to an attacker.
To exploit the vulnerability, in a web-based attack scenario, an attacker could host a website in an attempt to exploit the vulnerability. In addition, the user must be logged on to a website that does not securely populate URLs with confidential information. 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 the user to take action. For example, an attacker could trick a user into clicking a link that takes them to the attacker's site.
The update addresses the vulnerability by changing how the Fetch API in Microsoft Edge handles specific filtered response types.
## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for 32-bit Systems | 17134.285 | [KB4457128](https://patchblox.com/security/data/fix/microsoft/kb4457128.md) | Sep 11, 2018 | | Microsoft | Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for x64-based Systems | 17134.285 | [KB4457128](https://patchblox.com/security/data/fix/microsoft/kb4457128.md) | Sep 11, 2018 | --- 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo