CVE-2026-66311: Microsoft Edge (Chromium-based) Tampering Vulnerability

Overview

Severity

Medium (CVSS 6.2)

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C

Category

Edge - Chromium

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-Jul

Released

2026-07-31

Description

Missing authorization in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering locally.

FAQ

According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of confidentiality (C:H), but lead to no loss of integrity (I:N) or availability (A:N). What does that mean for this vulnerability? An attacker who successfully exploits this vulnerability cannot modify any sensitive user data or cause user data to become unavailable but can access sensitive user data. What is the version information for this release? Microsoft Edge Version Date Released Based on Chromium Version 151.0.4129.59 07/31/2026 151.0.7922.71/.72

Affected Products (1)

Browser

• Microsoft Edge (Chromium-based)

Acknowledgments

Kugelblitz with Microsoft, Kugelblitz with Microsoft

Revision History

• 2026-07-31: Information published.