Published Mar 10, 2026Sources checked Nov 13, 2026
8.8HIGHCVSS out of 10
What this means
Review the available evidence
CVE-2026-3847 and is rated High severity with a CVSS score of 8.8. 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: Nov 12, 2026
Release Notes
Vendor-listed releases
0:158.0.1-15.azl4
CISA KEVNot listedBased on the latest collected catalog
EPSS0.4%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-3847?
Memory safety bugs present in Firefox 148.0.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.