{
  "document": {
    "acknowledgments": [
      {
        "names": [
          "\u003ca href=\"https://ch.linkedin.com/in/martin-wrona-7746122b8\"\u003eMartin Wrona (martin_jw)\u003c/a\u003e with \u003ca href=\"https://www.galaxus.ch/\"\u003eDigitec Galaxus AG\u003c/a\u003e"
        ]
      }
    ],
    "aggregate_severity": {
      "namespace": "https://www.microsoft.com/en-us/msrc/security-update-severity-rating-system",
      "text": "Important"
    },
    "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-2026-20959 Microsoft SharePoint Server Spoofing Vulnerability - HTML",
        "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20959"
      },
      {
        "category": "self",
        "summary": "CVE-2026-20959 Microsoft SharePoint Server Spoofing Vulnerability - CSAF",
        "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-20959.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 Spoofing Vulnerability",
    "tracking": {
      "current_release_date": "2026-01-13T08:00:00.000Z",
      "generator": {
        "date": "2026-01-13T18:03:51.789Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-20959",
      "initial_release_date": "2026-01-13T08:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-01-13T08:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c16.0.5535.1001",
            "product": {
              "name": "Microsoft SharePoint Enterprise Server 2016 \u003c16.0.5535.1001",
              "product_id": "3"
            }
          },
          {
            "category": "product_version",
            "name": "16.0.5535.1001",
            "product": {
              "name": "Microsoft SharePoint Enterprise Server 2016 16.0.5535.1001",
              "product_id": "10950"
            }
          }
        ],
        "category": "product_name",
        "name": "Microsoft SharePoint Enterprise Server 2016"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c16.0.10417.20083",
            "product": {
              "name": "Microsoft SharePoint Server 2019 \u003c16.0.10417.20083",
              "product_id": "2"
            }
          },
          {
            "category": "product_version",
            "name": "16.0.10417.20083",
            "product": {
              "name": "Microsoft SharePoint Server 2019 16.0.10417.20083",
              "product_id": "11585"
            }
          }
        ],
        "category": "product_name",
        "name": "Microsoft SharePoint Server 2019"
      },
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c16.0.19127.20442",
            "product": {
              "name": "Microsoft SharePoint Server Subscription Edition \u003c16.0.19127.20442",
              "product_id": "1"
            }
          },
          {
            "category": "product_version",
            "name": "16.0.19127.20442",
            "product": {
              "name": "Microsoft SharePoint Server Subscription Edition 16.0.19127.20442",
              "product_id": "11961"
            }
          }
        ],
        "category": "product_name",
        "name": "Microsoft SharePoint Server Subscription Edition"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-20959",
      "cwe": {
        "id": "CWE-79",
        "name": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)"
      },
      "notes": [
        {
          "category": "general",
          "text": "Microsoft",
          "title": "Assigning CNA"
        },
        {
          "category": "faq",
          "text": "An authorized attacker must send the user a malicious link and convince the user to open it.",
          "title": "According to the CVSS metric, user interaction is required (UI:R) and privileges required is low (PR:L). What does that mean for this vulnerability?"
        },
        {
          "category": "faq",
          "text": "An attacker who successfully exploited the vulnerability could view some sensitive information (Confidentiality), make changes to disclosed information (Integrity), but cannot limit access to the resource (Availability).",
          "title": "According to the CVSS metrics, successful exploitation of this vulnerability could lead to some loss of confidentiality (C:L), and integrity (I:L) but lead to no loss of availability (A:N). What is the impact of this vulnerability?"
        }
      ],
      "product_status": {
        "fixed": [
          "10950",
          "11585",
          "11961"
        ],
        "known_affected": [
          "1",
          "2",
          "3"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-20959 Microsoft SharePoint Server Spoofing Vulnerability - HTML",
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20959"
        },
        {
          "category": "self",
          "summary": "CVE-2026-20959 Microsoft SharePoint Server Spoofing Vulnerability - CSAF",
          "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-20959.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-01-13T08:00:00.000Z",
          "details": "16.0.5535.1001:Security Update:https://support.microsoft.com/help/5002828",
          "product_ids": [
            "3"
          ],
          "url": "https://support.microsoft.com/help/5002828"
        },
        {
          "category": "vendor_fix",
          "date": "2026-01-13T08:00:00.000Z",
          "details": "16.0.10417.20083:Security Update:https://support.microsoft.com/help/5002825",
          "product_ids": [
            "2"
          ],
          "url": "https://support.microsoft.com/help/5002825"
        },
        {
          "category": "vendor_fix",
          "date": "2026-01-13T08:00:00.000Z",
          "details": "16.0.19127.20442:Security Update:https://support.microsoft.com/help/5002822",
          "product_ids": [
            "1"
          ],
          "url": "https://support.microsoft.com/help/5002822"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.6,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "environmentalsScore": 0.0,
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 4.0,
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "1",
            "2",
            "3"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Spoofing"
        },
        {
          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Less Likely"
        }
      ],
      "title": "Microsoft SharePoint Server Spoofing Vulnerability"
    }
  ]
}