A denial of service vulnerability exists in the Windows implementation of Transport Layer Security (TLS) when it improperly handles certain key exchanges. An attacker who successfully exploited the vulnerability could cause a target system to stop responding. To exploit this vulnerability, a remote unauthenticated attacker could send a specially crafted request to a target system utilizing TLS 1.2 or lower, triggering the system to automatically reboot. The update addresses the vulnerability by changing the way TLS key exchange messages are validated.
https://www.tenable.com/blog/microsoft-s-may-2020-patch-tuesday-addresses-111-cves
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1118
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1118