{
  "cveId": "CVE-2021-26887",
  "url": "https://patchblox.com/security/cve/CVE-2021-26887",
  "summary": "CVE-2021-26887 is fixed in 2 products on 1 platform, first by KB5000840, released March 9, 2021. It is not reported as exploited. Patch Radar priority: High.",
  "title": "Microsoft Windows Folder Redirection Elevation of Privilege Vulnerability",
  "description": "\u003Cp\u003EAn elevation of privilege vulnerability exists in Microsoft Windows when Folder redirection has been enabled via Group Policy. When folder redirection file server is co-located with Terminal server, an attacker who successfully exploited the vulnerability would be able to begin redirecting another user\u0027s personal data to a created folder.\u003C/p\u003E\n\u003Cp\u003ETo exploit the vulnerability, an attacker can create a new folder under the Folder Redirection root path and create a junction on a newly created User folder. When the new user logs in, Folder Redirection would start redirecting to the folder and copying personal data.\u003C/p\u003E\n\u003Cp\u003EThis elevation of privilege vulnerability can only be addressed by reconfiguring Folder Redirection with Offline files and restricting permissions, and NOT via a security update for affected Windows Servers. See the \u003Cstrong\u003EFAQ\u003C/strong\u003E section of this CVE for configuration guidance.\u003C/p\u003E",
  "published": "2021-03-15T12:00:00Z",
  "severity": "Important",
  "cvss": 7.8,
  "epss": 0.01065,
  "epssPercentile": 0.64924,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "exploitabilityAssessment": "Exploitation Less Likely",
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26887",
  "fixes": [
    {
      "platform": "microsoft",
      "product": "Windows Server 2012",
      "fixedVersion": "",
      "fix": "KB5000840",
      "url": "https://patchblox.com/security/fix/microsoft/kb5000840",
      "released": "2021-03-09T14:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012",
      "fixedVersion": "",
      "fix": "KB5000847",
      "url": "https://patchblox.com/security/fix/microsoft/kb5000847",
      "released": "2021-03-09T14:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5000840",
      "url": "https://patchblox.com/security/fix/microsoft/kb5000840",
      "released": "2021-03-09T14:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5000847",
      "url": "https://patchblox.com/security/fix/microsoft/kb5000847",
      "released": "2021-03-09T14:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T13:31:49Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}