{"@odata.context":"https://api.msrc.microsoft.com/sug/v2.0/sugodata/v2.0/en-US/$metadata#vulnerability/$entity","id":"00000000-0000-0000-0000-0000f0ffdadc","releaseDate":"2026-07-14T07:00:00-07:00","cveNumber":"CVE-2026-55040","cveTitle":"Microsoft SharePoint Server Security Feature Bypass Vulnerability","releaseNumber":"2026-Jul","vulnType":"Security Vulnerability","latestRevisionDate":"2026-07-14T07:00:00-07:00","description":"<p>Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.</p>\n","cweList":["CWE-1390: Weak Authentication"],"cweDetailsListForSearch":["cwe: CWE-1390: Weak Authentication","cweUrl: https://cwe.mitre.org/data/definitions/1390.html"],"unformattedDescription":"Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.","mitreText":"CVE-2026-55040","mitreUrl":"https://www.cve.org/CVERecord?id=CVE-2026-55040","publiclyDisclosed":"No","exploited":"No","latestSoftwareReleaseId":1,"latestSoftwareRelease":"Exploitation More Likely","olderSoftwareReleaseId":0,"denialOfService":"N/A","tag":"Microsoft Office SharePoint","issuingCna":"Microsoft","issuingCnaId":100000001,"severityId":100000000,"severity":"Critical","impactId":100000007,"impact":"Security Feature Bypass","langCode":"en-US","baseScore":"9.1","temporalScore":"7.9","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C","vectorStringSource":"Microsoft","isMariner":false,"customerActionRequired":true,"customerActionRequiredId":1,"cweDetailsList":[{"keys":["cwe","cweUrl"],"values":["CWE-1390: Weak Authentication","https://cwe.mitre.org/data/definitions/1390.html"]}],"articles":[{"title":"Microsoft Office SharePoint Security Feature Bypass Vulnerability","articleType":"100000000","description":"<p>Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.</p>\n","ordinal":10000},{"title":"Authentication Bypass","articleType":"FAQ","description":"<p><strong>What kind of security feature could be bypassed by successfully exploiting this vulnerability?</strong></p>\n<p>The authentication feature could be bypassed as this vulnerability allows impersonation.</p>\n","ordinal":10000},{"articleType":"FAQ","description":"<p><strong>I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running?</strong></p>\n<p>Yes. The same KB number applies to both SharePoint Server 2016 and SharePoint Enterprise Server 2016. Customers running either version should install the security update to be protected from this vulnerability.</p>\n","ordinal":10000},{"articleType":"FAQ","description":"<p><strong>According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of confidentiality (C:H), and integrity (I:H), but could lead to no loss of availability (A:N). What does that mean for this vulnerability?</strong></p>\n<p>Exploiting this vulnerability could allow an attacker to disclose files and modify data, but the attacker cannot impact the availability of the system.</p>\n","ordinal":10000},{"articleType":"FAQ","description":"<p><strong>How could an attacker exploit this vulnerability?</strong></p>\n<p>In a network-based attack, an unauthenticated attacker could bypass authentication and make an anonymous connection.</p>\n","ordinal":10000}],"revisions":[{"cveNumber":"CVE-2026-55040","version":1,"revisionDate":"2026-07-14T07:00:00-07:00","initialDate":"0001-01-01T00:00:00Z","description":"<p>Information published.</p>\n","unformattedDescription":"Information published.","notificationNeeded":false,"notificationSent":false,"sourceId":"e07e109a-726a-f111-93fe-000d3afbc7d7"}]}