CVE-2026-21509 — Microsoft Office Security Feature Bypass Vulnerability
Severity: Critical · Kind: Vulnerability
What it is
AI offline placeholder summary for: Title: CVE-2026-21509 — Microsoft Office Security Feature Bypass Vulnerability K.
Who this affects
AI summarisation is currently disabled — see the source link for the full upstream advisory.
What to do
Re-run summarisation from /admin/threats once ANTHROPIC_API_KEY is configured.
From the source
Microsoft Office. 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. 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.
Vulnerability facts
- CVE
- CVE-2026-21509
- On CISA KEV since
- 2026-01-26
- Ransomware use
- Unknown
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Plain-English summaries are AI-generated and reviewed for tone, not technical accuracy. For incident response, always rely on the original source linked above.