CVE-2026-100208 and is rated High severity with a CVSS score of 8.1. 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: Sep 25, 2026
Click to Run
Vendor-listed releases
https://aka.ms/OfficeSecurityReleases
CISA KEVNot listedBased on the latest collected catalog
EPSS0.5%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-100208?
Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.