Origin validation error in Microsoft Edge - CVE-2026-66318
Published: July 31, 2026 / Updated: August 2, 2026
Vulnerability identifier: #VU140711
CSH Severity: High
CVSS v4 BT: 6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber]
CVE-ID: CVE-2026-66318
CWE-ID: CWE-346
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to an origin validation error in Microsoft Edge (Chromium-based) when handling authorization requests. A remote attacker can trick a user into interacting with a malicious request to disclose sensitive information.
User interaction is required to visit an attacker-controlled webpage and perform two tap gestures that activate autofill, which can cause the application to obtain an access token on the user's behalf and send it to an attacker-controlled location.
Affected software
Microsoft Edge
How to mitigate CVE-2026-66318
Install security update from vendor's website.
Microsoft Edge - update to 151.0.4129.59