Published Oct 22, 2026Sources checked Oct 31, 2026
9.5CRITICALCVSS out of 10
What this means
Review the available evidence
CVE-2026-97631 and is rated Critical severity with a CVSS score of 9.5. 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: Oct 31, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSS0.6%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-97631?
EDK2 contains a vulnerability in BIOS where a user may cause “Out-of-bounds Write”, Classic Buffer Overflow, and “Incorrect Calculation of Buffer Size” by remote access. Successful exploitation of this vulnerability can lead to arbitrary code execution.
It could also impact Confidentiality, Integrity, and Availability.