{"id":"CVE-2026-21509","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-21509","summary":"Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.","details":"Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.","published":"2026-01-26T18:16:38.540","modified":"2026-06-25T05:16:53.167","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},"epss":{"score":0.72554,"percentile":0.99408,"asOf":"2026-09-14"},"cisaKev":null,"exploitsKnown":6,"affectedPackages":[],"fix":null,"references":[{"type":"ADVISORY","url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21509"},{"type":"ADVISORY","url":"https://www.vicarius.io/vsociety/posts/cve-2026-21509-detection-script-microsoft-office-security-feature-bypass-vulnerability"},{"type":"ADVISORY","url":"https://www.vicarius.io/vsociety/posts/cve-2026-21509-mitigation-script-microsoft-office-security-feature-bypass-vulnerability"},{"type":"WEB","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21509"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-06-25T05:16:53.167"}}