Main Vulnerability Database Vulnerabilities #VU131287

Improper access control in Microsoft products - CVE-2026-40420

Published: May 12, 2026

Vulnerability identifier: #VU131287

CSH Severity: Low

CVSS v4: 8.5 [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]

CVE-ID: CVE-2026-40420

CWE-ID: CWE-284

Exploitation vector: Local access

Exploit availability: No public exploit available

Vulnerability details

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.

Affected software

Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft Office LTSC

How to mitigate CVE-2026-40420

Install updates from vendor's website.

External References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40420

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