CVE-2026-66798: Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability

Overview

Severity
Medium (CVSS 4.3)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C
Category
Edge - Chromium
Exploit Status
Not Exploited
Exploitation Likelihood
Unlikely
Patch Tuesday
2026-Aug
Released
2026-08-28
EPSS Score
0.57% (percentile: 44.5%)

Description

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

FAQ

According to the CVSS metric, the attack vector is network (AV:N) and the user interaction is required (UI:R). What is the target context of the remote code execution? This attack requires a client to connect to a malicious server, and that could allow the attacker to gain code execution on the client. According to the CVSS metrics, successful exploitation of this vulnerability could lead to no loss of confidentiality (C:N) and integrity (I:N), but could lead to some loss of availability (A:L). What does that mean for this vulnerability? While we cannot rule out the impact to Confidentiality, Integrity, and Availability, the ability to exploit this vulnerability by itself is limited. An attacker would need to combine this with other vulnerabilities to perform an attack. According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do? The user must visit the attacker‑controlled webpage, and perform the two tap gestures that cause autofill to activate. What is the version information for this release? Microsoft Edge Version Date Released Based on Chromium Version 152.0.4191.53 08/28/2026 152.0.7977.64/.65

Affected Products (1)

Browser

  • Microsoft Edge (Chromium-based)

Acknowledgments

Kugelblitz with Microsoft, Kugelblitz with Microsoft

Revision History

  • 2026-08-28: Information published.