No access to your tenant or devices. Every item links to its source. What this means
CISA lists this Microsoft vulnerability as known exploited. Its MSRC release detail is outside this installation's collected history.
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.
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Explore global source statements, affected packages and advisory history for CVE-2026-21509. The catalog has a separate collection scope from Microsoft release records.
Publishers link these advisories through the identifiers shown below. A shared identifier or date alone does not tell you whether your software is affected or whether the advisories describe the same cause.
CVE-2026-21509 · CVE overview and exploitation status