{
  "document": {
    "acknowledgments": [
      {
        "names": [
          "\u003ca href=\"https://x.com/rm_rf_chumy\"\u003eChumy Tsai\u003c/a\u003e with \u003ca href=\"https://www.cycraft.com/\"\u003eCyCraft Technology\u003c/a\u003e\n"
        ]
      },
      {
        "names": [
          "\u003ca href=\"https://twitter.com/_l0gg\"\u003ekhoadha\u003c/a\u003e"
        ]
      },
      {
        "names": [
          "\u003ca href=\"https://x.com/stephenfewer\"\u003eStephen Fewer\u003c/a\u003e with \u003ca href=\"https://www.rapid7.com/\"\u003eRapid7\u003c/a\u003e"
        ]
      }
    ],
    "aggregate_severity": {
      "namespace": "https://www.microsoft.com/en-us/msrc/security-update-severity-rating-system",
      "text": "Critical"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      },
      {
        "category": "general",
        "text": "Required. The vulnerability documented by this CVE requires customer action to resolve.",
        "title": "Customer Action"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-55040 Microsoft SharePoint Server Security Feature Bypass Vulnerability - HTML",
        "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040"
      },
      {
        "category": "self",
        "summary": "CVE-2026-55040 Microsoft SharePoint Server Security Feature Bypass Vulnerability - CSAF",
        "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-55040.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Exploitability Index",
        "url": "https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "Microsoft SharePoint Server Security Feature Bypass Vulnerability",
    "tracking": {
      "current_release_date": "2026-07-14T07:00:00.000Z",
      "generator": {
        "date": "2026-07-14T20:05:38.238Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-55040",
      "initial_release_date": "2026-07-14T07:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-07-14T07:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c16.0.5561.1001",
            "product": {
              "name": "Microsoft SharePoint Enterprise Server 2016 \u003c16.0.5561.1001",
              "product_id": "3"
            }
          },
          {
            "category": "product_version",
            "name": "16.0.5561.1001",
            "product": {
              "name": "Microsoft SharePoint Enterprise Server 2016 16.0.5561.1001",
              "product_id": "10950"
            }
          }
        ],
        "category": "product_name",
        "name": "Microsoft SharePoint Enterprise Server 2016"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c16.0.10417.20175",
            "product": {
              "name": "Microsoft SharePoint Server 2019 \u003c16.0.10417.20175",
              "product_id": "2"
            }
          },
          {
            "category": "product_version",
            "name": "16.0.10417.20175",
            "product": {
              "name": "Microsoft SharePoint Server 2019 16.0.10417.20175",
              "product_id": "11585"
            }
          }
        ],
        "category": "product_name",
        "name": "Microsoft SharePoint Server 2019"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c16.0.19725.20434",
            "product": {
              "name": "Microsoft SharePoint Server Subscription Edition \u003c16.0.19725.20434",
              "product_id": "1"
            }
          },
          {
            "category": "product_version",
            "name": "16.0.19725.20434",
            "product": {
              "name": "Microsoft SharePoint Server Subscription Edition 16.0.19725.20434",
              "product_id": "11961"
            }
          }
        ],
        "category": "product_name",
        "name": "Microsoft SharePoint Server Subscription Edition"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-55040",
      "cwe": {
        "id": "CWE-1390",
        "name": "Weak Authentication"
      },
      "notes": [
        {
          "category": "general",
          "text": "Microsoft",
          "title": "Assigning CNA"
        },
        {
          "category": "faq",
          "text": "The authentication feature could be bypassed as this vulnerability allows impersonation.",
          "title": "What kind of security feature could be bypassed by successfully exploiting this vulnerability?"
        },
        {
          "category": "faq",
          "text": "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.",
          "title": "I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running?"
        },
        {
          "category": "faq",
          "text": "Exploiting this vulnerability could allow an attacker to disclose files and modify data, but the attacker cannot impact the availability of the system.",
          "title": "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?"
        },
        {
          "category": "faq",
          "text": "In a network-based attack, an unauthenticated attacker could bypass authentication and make an anonymous connection.",
          "title": "How could an attacker exploit this vulnerability?"
        }
      ],
      "product_status": {
        "fixed": [
          "10950",
          "11585",
          "11961"
        ],
        "known_affected": [
          "1",
          "2",
          "3"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-55040 Microsoft SharePoint Server Security Feature Bypass Vulnerability - HTML",
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040"
        },
        {
          "category": "self",
          "summary": "CVE-2026-55040 Microsoft SharePoint Server Security Feature Bypass Vulnerability - CSAF",
          "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-55040.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-07-14T07:00:00.000Z",
          "details": "16.0.5561.1001:Security Update:https://support.microsoft.com/help/5002891",
          "product_ids": [
            "3"
          ],
          "url": "https://support.microsoft.com/help/5002891"
        },
        {
          "category": "vendor_fix",
          "date": "2026-07-14T07:00:00.000Z",
          "details": "16.0.10417.20175:Security Update:https://support.microsoft.com/help/5002883",
          "product_ids": [
            "2"
          ],
          "url": "https://support.microsoft.com/help/5002883"
        },
        {
          "category": "vendor_fix",
          "date": "2026-07-14T07:00:00.000Z",
          "details": "16.0.19725.20434:Security Update:https://support.microsoft.com/help/5002882",
          "product_ids": [
            "1"
          ],
          "url": "https://support.microsoft.com/help/5002882"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "environmentalScore": 0.0,
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 7.9,
            "userInteraction": "NONE",
            "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",
            "version": "3.1"
          },
          "products": [
            "1",
            "2",
            "3"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Security Feature Bypass"
        },
        {
          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation More Likely"
        }
      ],
      "title": "Microsoft SharePoint Server Security Feature Bypass Vulnerability"
    }
  ]
}