CVE-2026-21509
KEVMicrosoft Office Security Feature Bypass Vulnerability
7.8
HighPublished:
Last updated:
Source:secure@microsoft.com
Analyzed
Weakness (CWE)
CVSS Vector
v3.1- Attack Vector
- Local
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Description
Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.
References
secure@microsoft.com
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21509af854a3a-2127-422b-91ae-364da2661108
https://www.vicarius.io/vsociety/posts/cve-2026-21509-detection-script-microsoft-office-security-feature-bypass-vulnerabilityaf854a3a-2127-422b-91ae-364da2661108
https://www.vicarius.io/vsociety/posts/cve-2026-21509-mitigation-script-microsoft-office-security-feature-bypass-vulnerability134c704f-9b21-4f2e-91b3-4a467353bcc0
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21509