{"id":229867,"date":"2026-01-27T02:21:45","date_gmt":"2026-01-27T08:21:45","guid":{"rendered":"https:\/\/lifeboat.com\/blog\/2026\/01\/microsoft-patches-actively-exploited-office-zero-day-vulnerability"},"modified":"2026-01-27T02:21:45","modified_gmt":"2026-01-27T08:21:45","slug":"microsoft-patches-actively-exploited-office-zero-day-vulnerability","status":"publish","type":"post","link":"https:\/\/lifeboat.com\/blog\/2026\/01\/microsoft-patches-actively-exploited-office-zero-day-vulnerability","title":{"rendered":"Microsoft patches actively exploited Office zero-day vulnerability"},"content":{"rendered":"<p><a class=\"aligncenter blog-photo\" href=\"https:\/\/lifeboat.com\/blog.images\/microsoft-patches-actively-exploited-office-zero-day-vulnerability.jpg\"><\/a><\/p>\n<p>Microsoft has released emergency out-of-band security updates to patch a high-severity Microsoft Office zero-day vulnerability exploited in attacks.<\/p>\n<p>The security feature bypass vulnerability, tracked as <a href=\"http:\/\/msrc.microsoft.com\/update-guide\/vulnerability\/CVE-2026-21509\" target=\"_blank\" rel=\"nofollow noopener\">CVE-2026\u201321509<\/a>, affects multiple Office versions, including Microsoft Office 2016, Microsoft Office 2019, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, and Microsoft 365 Apps for Enterprise (the company\u2019s cloud-based subscription service).<\/p>\n<p>However, as noted in today\u2019s advisory, security updates for Microsoft Office 2016 and 2019 are not yet available and will be released as soon as possible.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Microsoft has released emergency out-of-band security updates to patch a high-severity Microsoft Office zero-day vulnerability exploited in attacks. The security feature bypass vulnerability, tracked as CVE-2026\u201321509, affects multiple Office versions, including Microsoft Office 2016, Microsoft Office 2019, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, and Microsoft 365 Apps for Enterprise (the company\u2019s cloud-based subscription [\u2026]<\/p>\n","protected":false},"author":427,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1492],"tags":[],"class_list":["post-229867","post","type-post","status-publish","format-standard","hentry","category-security"],"_links":{"self":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/229867","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/users\/427"}],"replies":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/comments?post=229867"}],"version-history":[{"count":0,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/229867\/revisions"}],"wp:attachment":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/media?parent=229867"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/categories?post=229867"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/tags?post=229867"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}