CVE-2026-21509

Microsoft Office Security Feature Bypass Vulnerability

Published

2026-01-26

Modified

2026-07-31

Sources

cisa-kev

Summary

Microsoft Office contains a security feature bypass vulnerability in which reliance on untrusted inputs in a security decision in Microsoft Office could allow an unauthorized attacker to bypass a security feature locally. Some of the impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.

References

• https://www.cisa.gov/known-exploited-vulnerabilities-catalog