CVE-2021-26887
Microsoft Windows Folder Redirection Elevation of Privilege Vulnerability
At a glance
- Source
- NVD
- EPSS
- EPSS 1.06 % · percentile 65 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- microsoft
- NVD status
- Modified
Description
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. To 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. This 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.
Weaknesses (CWE)
- CWE-59 — Improper Link Resolution Before File Access
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C | microsoft |
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | NVD · secure@microsoft.com (Secondary) |
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | NVD · nvd@nist.gov (Secondary) |
| CVSS 2.0 | MEDIUM 4.6 | AV:L/AC:L/Au:N/C:P/I:P/A:P | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2021-13671
- GCVE · GCVE-0-2021-26887
CERT-FR advisories
- CERTFR-2021-AVI-181 — Multiples vulnérabilités dans Microsoft Windows · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_10:1803:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*
Affected products
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |