CVE-2026-40420: Microsoft Office Click-To-Run Elevation of Privilege Vulnerability
Microsoft Office Click-To-Run Elevation of Privilege Vulnerability
Other sources
Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.
— Microsoft
Affected Software
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
Frequently Asked Questions
What is the severity of CVE-2026-40420?
CVE-2026-40420 has a high severity rating of 8.8.
How do I fix CVE-2026-40420?
To mitigate CVE-2026-40420, ensure that you apply the latest updates for Microsoft Office Click-To-Run.
What software is affected by CVE-2026-40420?
CVE-2026-40420 affects various editions of Microsoft Office, including Microsoft 365 Apps and Microsoft Office LTSC 2021 and 2024.
What kind of vulnerability is CVE-2026-40420?
CVE-2026-40420 is an elevation of privilege vulnerability caused by improper access control in Microsoft Office Click-To-Run.
Can CVE-2026-40420 be exploited remotely?
CVE-2026-40420 requires local access for exploitation, as it allows an authorized attacker to elevate privileges locally.