CVE-2026-21509 added to CISA KEV: Microsoft Office
Status: ✅ Confirmed exploited in the wild
Date added: 2026-01-26
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Due date: 2026-02-16
Why this matters
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.
Sources
Lyrie Verdict
Lyrie's autonomous detection layer catches active exploitation primitives at machine speed — closing the gap between disclosure and weaponization that traditional defense simply can't cover.