Published Aug 28, 2026Sources checked Oct 28, 2026
5.4MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-70309 and is rated Medium severity with a CVSS score of 5.4. 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: Aug 28, 2026
Release Notes
Vendor-listed releases
150.0.4078.65
CISA KEVNot listedBased on the latest collected catalog
EPSS0.2%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-70309?
Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to bypass a security feature over a network.