CVE-2026-40420 Details
Description
Use after free in Microsoft Office allows an authorized attacker to elevate privileges locally.
A vulnerability allowing improper access control has been identified in Microsoft Office Click-To-Run. This issue enables an authorized attacker to locally elevate privileges. The vulnerability affects multiple Office products, including Office LTSC 2024, Office LTSC 2021, Microsoft 365 Apps for Enterprise, Office 2019, and various Click-To-Run editions.
Users can download the security update for their specific Office version from the Microsoft Update Catalog. For guidance on which version to download, refer to the Microsoft Office Security Updates page.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 7, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40420 | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-284 | Improper Access Control | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| microsoft 365 apps | All versions |
CPE
Remediation
| |
| microsoft office | 2019 |
CPE
Remediation
| |
| microsoft office long term servicing channel | 2021 2024 |
CPE
Remediation
| |
Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 1, 2026 | CVE Modified | [email protected] |
| May 19, 2026 | Initial Analysis | [email protected] |
| May 12, 2026 | New CVE Received | [email protected] |