Improper access control in Microsoft products - CVE-2026-40420
Published: May 12, 2026
Vulnerability identifier: #VU131287
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-40420
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Microsoft
Affected software:
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft Office LTSC
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft Office LTSC
Detailed vulnerability description
The vulnerability allows a local user to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to improper access restrictions in Microsoft Office Click-To-Run. A local user can bypass implemented security restrictions and gain elevated privileges on the system.
How to mitigate CVE-2026-40420
Install updates from vendor's website.