{
  "id": "cve-2026-20963",
  "cveID": "CVE-2026-20963",
  "vendor": "Microsoft",
  "product": "SharePoint",
  "vulnerabilityName": "Microsoft SharePoint Deserialization of Untrusted Data Vulnerability",
  "shortDescription": "Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.",
  "requiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
  "dateAdded": "2026-03-18",
  "dueDate": "2026-03-21",
  "knownRansomware": false,
  "cwes": [
    "CWE-502"
  ],
  "notes": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963 ; https://nvd.nist.gov/vuln/detail/CVE-2026-20963",
  "sources": [
    {
      "label": "NVD",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20963"
    },
    {
      "label": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog"
    },
    {
      "label": "msrc.microsoft.com",
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963"
    },
    {
      "label": "nvd.nist.gov",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20963"
    }
  ],
  "cvss": {
    "score": 9.8,
    "severity": "CRITICAL",
    "version": "3.1",
    "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  },
  "epss": {
    "score": 0.31554,
    "percentile": 0.98177
  },
  "timeline": [
    {
      "date": "2026-03-18",
      "event": "Added to the CISA KEV catalog"
    },
    {
      "date": "2026-03-21",
      "event": "CISA remediation due date (BOD 22-01)"
    }
  ],
  "status": "past due"
}