Patch Tuesday for May 2021 security updates addressed 55 vulnerabilities in Microsoft including a critical HTTP Protocol Stack Remote Code Execution vulnerability tracked as CVE-2021-31166. The flaw is wormable and affects different versions of Windows 10, Windows Server 2004 and Windows Server 20H2. The issue also impacts Windows 10 and Server devices running the Windows Remote Management (WinRM) service. At the time of this writing, more than 1,6 million Windows systems running the WinRM service are exposed online.”]
Source: https://securityaffairs.co/wordpress/118189/security/cve-2021-31166-windows-http-flaw.html