Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows 10 | - |
| Microsoft | Windows 7 | - |
| Microsoft | Windows 8.1 | - |
| Microsoft | Windows Rt 8.1 | - |
| Microsoft | Windows Server 2008 | - |
| Microsoft | Windows Server 2012 | - |
| Microsoft | Windows Server 2016 | - |
| Microsoft | Windows Server 2019 | - |
Related Weaknesses (CWE)
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26887
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-2688PatchVendor Advisory
FAQ
What is CVE-2021-26887?
CVE-2021-26887 is a vulnerability with a CVSS score of 7.8 (HIGH). 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, a...
How severe is CVE-2021-26887?
CVE-2021-26887 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-26887?
Check the references section above for vendor advisories and patch information. Affected products include: Microsoft Windows 10, Microsoft Windows 7, Microsoft Windows 8.1, Microsoft Windows Rt 8.1, Microsoft Windows Server 2008.