CVE-2021-26887
7.8 · HIGHOverview
CVE-2021-26887 is a high-severity vulnerability affecting microsoft windows_10. It was published on March 11, 2021 and has a CVSS 3.1 base score of 7.8 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from microsoft. Update windows_10 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
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Frequently Asked Questions
What is CVE-2021-26887?
CVE-2021-26887 is a high-severity vulnerability affecting microsoft windows_10. It was published on March 11, 2021 and has a CVSS 3.1 base score of 7.8 (HIGH).
How severe is CVE-2021-26887?
This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2021-26887?
Check the references section for vendor advisories and patches from microsoft. Update windows_10 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-26887?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-26887 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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