Windows Authentication Elevation of Privilege Vulnerability

What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation of this vulnerability requires an attacker to take additional actions prior to exploitation to prepare the target environment.

Security updates
10.0.17763.4499 — https://support.microsoft.com/help/5027222
10.0.20348.1787 — https://support.microsoft.com/help/5027225
10.0.20348.1784 — https://support.microsoft.com/help/5027319
10.0.22000.2057 — https://support.microsoft.com/help/5027223
10.0.19044.3086 — https://support.microsoft.com/help/5027215
10.0.22621.1848 — https://support.microsoft.com/help/5027231
10.0.10240.19983 — https://support.microsoft.com/help/5027230
10.0.14393.5989 — https://support.microsoft.com/help/5027219
6.1.7601.26564 — https://support.microsoft.com/help/5027275
6.1.7601.26564 — https://support.microsoft.com/help/5027256
6.2.9200.24314 — https://support.microsoft.com/help/5027283
6.2.9200.24314 — https://support.microsoft.com/help/5027281
6.3.9600.21013 — https://support.microsoft.com/help/5027271
6.3.9600.21013 — https://support.microsoft.com/help/5027282