CVE-2026-21509 — Actively Exploited: Office (Microsoft)
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
| CVE ID | CVE-2026-21509 |
|---|---|
| Vendor | Microsoft |
| Product | Office |
| Vulnerability name | Microsoft Office Security Feature Bypass Vulnerability |
| Date added | 2026-01-26 |
| Remediation due | 2026-02-16 |
| Known ransomware use | Unknown |
| 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. |
| 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. |
| Source | CISA Known Exploited Vulnerabilities |
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