CVE-2026-21509
Act now ● On CISA KEV — actively exploited
Actively exploited — on the CISA KEV list.
CVSS base
—
EPSS — probability of exploitation (30 days)
72.6%
99.4th percentile
CISA KEV
Listed
Added 2026-01-26 · patch by 2026-02-16
Weakness / dates
—
Published — · modified —
Description
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.