Published Jun 17, 2026Sources checked Nov 12, 2026
4.2MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-12456 and is rated Medium severity with a CVSS score of 4.2. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: Jun 19, 2026
Release Notes
Vendor-listed releases
149.0.4022.80
CISA KEVNot listedBased on the latest collected catalog
EPSS0.1%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-12456?
Inappropriate implementation in Extensions in Google Chrome prior to 149.0.7827.155 allowed an attacker who convinced a user to install a malicious extension to bypass same origin policy via a crafted Chrome Extension. (Chromium security severity: High)