CVE-2026-100208: Microsoft Office Outlook Remote Code Execution Vulnerability
Published Sep 25, 2026
·Updated
Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
Other sources
Microsoft Office Outlook Remote Code Execution Vulnerability
— Microsoft
Affected Software
7 affected componentsFixes available
Microsoft Office Outlook
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2024 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2021 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2024 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2021 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in https://aka.ms/OfficeSecurityReleases
Event History
Sep 25, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·07:39 PM
Data Sourced
via MITRE·07:39 PM
DescriptionSeverity
Frequently Asked Questions
1
Does exploitation require an authenticated attacker or user interaction?
The attacker does not need authorization, but exploitation requires user interaction. The vulnerability is rated network-accessible with high attack complexity.
2
Which Outlook deployments are identified as affected?
The affected software list includes Microsoft 365 Apps for Enterprise, Microsoft Office Outlook, and Microsoft Office LTSC 2021 and 2024 in both 32-bit and 64-bit editions.