{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2021-26887", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-26887", "idYear": 2021, "status": "PUBLISHED", "publishedAt": "2021-03-11T15:42:16.000Z", "updatedAt": "2026-08-19T16:30:31.969Z", "importedAt": "2026-10-24T01:56:26.894Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "Microsoft Windows Folder Redirection Elevation of Privilege Vulnerability", "summary": "An 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's personal data to a created folder.\nTo 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.\nThis 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 FAQ section of this CVE for configuration guidance.", "affected": [ { "vendor": "Microsoft", "product": "Windows 10 Version 1507", "platforms": [ "32-bit Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 10 Version 1607", "platforms": [ "32-bit Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 10 Version 1803", "platforms": [ "32-bit Systems", "ARM64-based Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 10 Version 1809", "platforms": [ "32-bit Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 10 Version 1809", "platforms": [ "ARM64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 10 Version 1909", "platforms": [ "32-bit Systems", "ARM64-based Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 10 Version 2004", "platforms": [ "32-bit Systems", "ARM64-based Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 10 Version 20H2", "platforms": [ "32-bit Systems", "ARM64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 7", "platforms": [ "32-bit Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 7 Service Pack 1", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows 8.1", "platforms": [ "32-bit Systems", "ARM64-based Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2008 R2 Service Pack 1", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2008 R2 Service Pack 1 (Server Core installation)", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2008 Service Pack 2", "platforms": [ "32-bit Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2008 Service Pack 2 (Server Core installation)", "platforms": [ "32-bit Systems", "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2012", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "6.2.9200.0", "status": "affected", "versionType": "custom", "lessThan": "6.2.9200.23298" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2012 (Server Core installation)", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "6.2.9200.0", "status": "affected", "versionType": "custom", "lessThan": "6.2.9200.23298" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2012 R2", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2012 R2 (Server Core installation)", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2016", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2016 (Server Core installation)", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2019", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server 2019 (Server Core installation)", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server version 2004", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server version 20H2", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] }, { "vendor": "Microsoft", "product": "Windows Server, version 1909 (Server Core installation)", "platforms": [ "x64-based Systems" ], "versions": [ { "version": "-", "status": "affected" } ] } ] } } }