" Microsoft Corp. warns that attackers are exploiting a previously unknown vulnerability in Windows 10 and many Windows Server versions to seize control over PCs when users open a malicious document or visit a booby-trapped website. There is currently no official patch for the flaw, but Microsoft has released recommendations for mitigating the threat."
Here’s the CVE entry:
“Microsoft has not yet released a patch for CVE-2021-40444, but says users can mitigate the threat from this flaw by disabling the installation of all ActiveX controls in IE. Microsoft says the vulnerability is currently being used in targeted attacks, although its advisory credits three different entities with reporting the flaw.”