CVE-2021-26887 Microsoft Windows Folder Redirection Elevation of Privilege Vulnerability
An attacker can redirect another user's personal data to a malicious folder when Folder Redirection is enabled, requiring configuration changes to mitigate.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-26887?
CVE-2021-26887 is a high-severity vulnerability in Microsoft Windows 10, published on 11 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-59
Which versions are affected by CVE-2021-26887?
It affects 8 products.
Products include Microsoft Windows 10, Microsoft Windows 7, Microsoft Windows 8.1, Microsoft Windows Rt 8.1, Microsoft Windows Server 2008, Microsoft Windows Server 2012 and 2 more.
How do I fix CVE-2021-26887?
No fix has been published for CVE-2021-26887 yet. Limit exposure of the affected software until one is available.
Is CVE-2021-26887 being exploited?
There is no known exploitation of CVE-2021-26887 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows 10
- CVE-2015-2426 Microsoft Windows Adobe Type Manager Library Remote Code Execution
- CVE-2015-1769 Microsoft Windows Mount Manager Privilege Escalation
- CVE-2020-1467 Windows Hard Link Elevation of Privilege Vulnerability
- CVE-2021-26424 Windows TCP/IP Remote Code Execution Vulnerability
- CVE-2021-28476 Windows Hyper-V Remote Code Execution Vulnerability
Sources
Also known as GHSA-xphp-jrmh-9rjj.