CVE-2026-21509

Description

Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.

Affected Platforms

Weakness Type

CWE-807

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21509
• https://www.vicarius.io/vsociety/posts/cve-2026-21509-detection-script-microsoft…
• https://www.vicarius.io/vsociety/posts/cve-2026-21509-mitigation-script-microsof…
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-…