CVE-2021-28311: 
vulnerability analysis and mitigation

A Windows Application Compatibility Cache Denial of Service Vulnerability, identified as CVE-2021-28311, was discovered and disclosed in April 2021. The vulnerability affects multiple versions of Microsoft Windows including Windows 10 (versions 1607, 1803, 1809, 1909, 2004, 20H2) and Windows Server (2016 and 2019) (Rapid7).

The vulnerability has been assigned a CVSS score of 4.0 (AV:N/AC:M/Au:N/C:N/I:N/A:P), indicating a medium severity level. This scoring suggests that the vulnerability is network accessible, requires moderate complexity to exploit, needs no authentication, and can only impact system availability without compromising confidentiality or integrity (Rapid7).

The vulnerability specifically affects the Windows Application Compatibility Cache and could allow an attacker to perform a denial of service attack against affected systems (Rapid7).

As of the disclosure date, there were no known exploits of this vulnerability in the wild (Rapid7).

Microsoft has released security updates to address this vulnerability. The fixes are available through various KB patches including KB5001347 (Windows 10 1607), KB5001339 (Windows 10 1803), KB5001342 (Windows 10 1809), KB5001337 (Windows 10 1909), KB5001330 (Windows 10 2004 and 20H2), and corresponding server versions (Rapid7).