CVE-2021-26887
<p>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.</p><p>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.</p><p>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 <strong>FAQ</strong> section of this CVE for configuration guidance.</p>
- CVSS v3.1
- 7.8 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS v3.1
- 7.8 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS v2.0
- 4.6 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P - EPSS
- 1.06% chance of exploitation in the next 30 days, 62th percentile
- Published
- 2021-03-11
- Updated
- 2026-08-19
Proof-of-concept exploits (1)
- Princeton-Cybbs/Asare_Prince0★ · 2024-10-01