CVE-2026-66313: Microsoft Edge (Chromium-based) Tampering Vulnerability

Overview

Severity

Medium (CVSS 6.8)

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/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

Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering locally.

FAQ

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 According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of confidentiality (C:H), and some loss of integrity (I:L), but no loss of availability (A:N). What does that mean for this vulnerability? An attacker who successfully exploited this vulnerability could view sensitive information, (Confidentiality), and make some changes to disclosed information (Integrity), but they would not be able to affect Availability.

Affected Products (1)

Browser

• Microsoft Edge (Chromium-based)

Acknowledgments

Kugelblitz with Microsoft, Kugelblitz with Microsoft

Revision History

• 2026-07-31: Information published.