CVE-2026-21509 - Microsoft Office
AI Vulnerability ContextReliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.
Overview
A source-backed snapshot of this vulnerability.
CISA KEVyesWhether CISA lists this as exploited.
Techniques0AI attack methods connected to this vulnerability.
Case studies0Examples where this vulnerability is mentioned.
Vulnerability status
How serious this vulnerability is and whether it is known to be exploited.
CISA KEVHIGH
- CVE ID
- CVE-2026-21509
- Vendor/project
- Microsoft
- Product
- Office
- Vulnerability name
- Microsoft Office Security Feature Bypass Vulnerability
- Date added
- 2026-01-26
- Due date
- 2026-02-16
- Known ransomware campaign use
- Unknown
- CVSS v3
- 7.8
CWE-807
Exploit context
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No description available. The source record only contains identifiers and metadata.
Source evidence
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Original source
Original source links
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NVD CVE pagehttps://nvd.nist.gov/vuln/detail/CVE-2026-21509CVE API docshttps://nvd.nist.gov/developers/vulnerabilitiesData feedshttps://nvd.nist.gov/vuln/data-feedsCataloghttps://www.cisa.gov/known-exploited-vulnerabilities-catalogData repositoryhttps://github.com/cisagov/kev-datasecure@microsoft.comhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21509af854a3a-2127-422b-91ae-364da2661108https://www.vicarius.io/vsociety/posts/cve-2026-21509-detection-script-microsoft-office-security-feature-bypass-vulnerabilityaf854a3a-2127-422b-91ae-364da2661108https://www.vicarius.io/vsociety/posts/cve-2026-21509-mitigation-script-microsoft-office-security-feature-bypass-vulnerability134c704f-9b21-4f2e-91b3-4a467353bcc0https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21509