Junglewise Threat Intelligence

CVE-2026-66321: Microsoft Edge type confusion vulnerability

CVE-2026-66321 · Severity: high · CVSS 7.4 · Published 2026-08-04

Technologies: Microsoft Edge Chromium, Microsoft Edge. Vendors: Microsoft.

Executive brief

Microsoft Edge is a web browser used by millions of users to access the internet and cloud services. A type confusion vulnerability in Edge's rendering engine could allow an attacker to execute arbitrary code on a user's computer by tricking them into visiting a malicious website, potentially compromising personal data, passwords, and system security.

Technical details

A type confusion vulnerability exists in Microsoft Edge (Chromium-based) where incompatible resource types are accessed without proper validation. This vulnerability is in the browser's rendering or JavaScript engine and can be triggered remotely over a network when a user visits a malicious webpage. No authentication is required for exploitation. A successful attack allows remote code execution with the privileges of the logged-in user. Patches are expected to be available through Microsoft's regular security update cycle.

Affected products

  • Microsoft Edge Chromium-based versions

Timeline

  • 2026-08-04: disclosed

References

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