IPSec in Microsoft Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT Gold and 8.1, and Windows 10 Gold and 1511 mishandles encryption negotiation, which allows remote authenticated users to cause a denial of service (system hang) via crafted IP traffic, aka "Windows IPSec Denial of Service Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-120