Threat actors have begun targeting internet-facing Microsoft SharePoint servers with exploit code for a critical authentication-bypass vulnerability less than 24 hours after detailed technical research and a public proof of concept were released.<\/p>\n\n\n\n
The vulnerability, tracked as CVE-2026-55040<\/a>, affects supported on-premises editions of Microsoft SharePoint Server and carries a critical CVSS severity score of 9.1. It allows a remote attacker who has no valid credentials to forge authentication tokens and impersonate a SharePoint user\u2014including, under the right conditions, a site administrator.<\/p>\n\n\n(10) Hackers Move Quickly To Exploit Critical Microsoft SharePoint Authentication Bypass | LinkedIn<\/a>: Hackers Move Quickly To Exploit Critical Microsoft SharePoint Authentication Bypass<\/span><\/a>","protected":false},"excerpt":{"rendered":" Threat actors have begun targeting internet-facing Microsoft SharePoint servers with exploit code for a critical authentication-bypass vulnerability less than 24 hours after detailed technical research and a public proof of concept were released. The vulnerability, tracked as CVE-2026-55040, affects supported on-premises editions of Microsoft SharePoint Server and carries a critical…<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[72],"class_list":["post-1167","post","type-post","status-publish","format-standard","hentry","category-vulnerability","tag-72"],"_links":{"self":[{"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/posts\/1167","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/comments?post=1167"}],"version-history":[{"count":1,"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/posts\/1167\/revisions"}],"predecessor-version":[{"id":1168,"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/posts\/1167\/revisions\/1168"}],"wp:attachment":[{"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/media?parent=1167"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/categories?post=1167"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/familiebuckens.nl\/index.php\/wp-json\/wp\/v2\/tags?post=1167"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}