Windows HTTP Stack Exploit Attempt - CVE-2021-31166

The HTTP Protocol Stack (HTTP.sys) is a kernel-mode device driver in Windows devices responsible for processing inbound HTTP requests and creating outbound HTTP responses. For example, HTTP.sys provides web server functionality to internet-facing applications such as Internet Information Services (IIS), Exchange, and SharePoint. A vulnerability exists in how HTTP.sys processes incoming HTTP requests with manipulated Accept-Encoding headers. An attacker crafts a combination of particular Accept-Encoding values that causes HTTP.sys to incorrectly process the request in a way that corrupts a critical data structure in the kernel. The corrupt data structure can lead to remote command execution (RCE) or a denial of service (DoS).