https://thenextweb.com/security/2019/09/24/microsoft-issues-emergency-windows-patch-to-address-internet-explorer-zero-day-flaw/

Microsoft has issued an emergency out-of-band security update to address two critical vulnerabilities impacting Internet Explorer and Windows Defender.

The flaws — indexed as CVE-2019-1367 and CVE-2019-1255 — made it possible for a remote attacker to take control of a target system and trigger a denial of service in Microsoft Defender, the antivirus app that ships with Windows software.