Microsoft Office
CVE-2026-21509 — Microsoft Office Security Feature Bypass Vulnerability
Executive Summary
Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.
Overview
7.8
CVSS HIGH
Important
MS Severity
Exploited
MS Exploit Status
Exploitation Detected
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
Required
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Functional
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.2
EPSS Score
0.72152
probability of exploitation in the next 30 days
0.99356 percentile - updated 2026-06-21
View on FIRST.org
Affected Products
10 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Microsoft 365 Apps for Enterprise for 32-bit Systems | Click to Run (Security Update) |
Important | Security Feature Bypass | No |
| Microsoft 365 Apps for Enterprise for 64-bit Systems | Click to Run (Security Update) |
Important | Security Feature Bypass | No |
| Microsoft Office 2016 (32-bit edition) | 5002713 (Security Update) |
Important | Security Feature Bypass | Maybe |
| Microsoft Office 2016 (64-bit edition) | 5002713 (Security Update) |
Important | Security Feature Bypass | Maybe |
| Microsoft Office 2019 for 32-bit editions | Click to Run (Security Update) |
Important | Security Feature Bypass | No |
| Microsoft Office 2019 for 64-bit editions | Click to Run (Security Update) |
Important | Security Feature Bypass | No |
| Microsoft Office LTSC 2021 for 32-bit editions | Click to Run (Security Update) |
Important | Security Feature Bypass | No |
| Microsoft Office LTSC 2021 for 64-bit editions | Click to Run (Security Update) |
Important | Security Feature Bypass | No |
| Microsoft Office LTSC 2024 for 32-bit editions | Click to Run (Security Update) |
Important | Security Feature Bypass | No |
| Microsoft Office LTSC 2024 for 64-bit editions | Click to Run (Security Update) |
Important | Security Feature Bypass | No |
Patches
2 patches
| Article | Type | Restart |
|---|---|---|
Click to Run |
Security Update | No |
5002713 |
Security Update | Maybe |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
Microsoft Threat Intelligence Center (MSTIC), Microsoft Security Response Center (MSRC), and Office Product Group Security Team, Google Threat Intelligence Group
References
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