Vulnerability Details : 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>
Vulnerability category: Gain privilege
Products affected by CVE-2021-26887
- 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_7:-:sp1:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:*:*
- 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_10:20h2:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-26887
0.07%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 31 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-26887
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
4.6
|
MEDIUM | AV:L/AC:L/Au:N/C:P/I:P/A:P |
3.9
|
6.4
|
NIST | |
7.8
|
HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
1.8
|
5.9
|
NIST | |
7.8
|
HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
1.8
|
5.9
|
Microsoft Corporation |
CWE ids for CVE-2021-26887
-
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.Assigned by: nvd@nist.gov (Primary)
References for CVE-2021-26887
-
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26887
CVE-2021-26887 - Security Update Guide - Microsoft - Microsoft Windows Folder Redirection Elevation of Privilege VulnerabilityPatch;Vendor Advisory
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