Microsoft Streaming Service 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 win a race condition.

Security updates
10.0.17763.5936 — https://support.microsoft.com/help/5039217
10.0.20348.2527 — https://support.microsoft.com/help/5039227
10.0.20348.2522 — https://support.microsoft.com/help/5039330
10.0.22000.3019 — https://support.microsoft.com/help/5039213
10.0.19044.4529 — https://support.microsoft.com/help/5039211
10.0.22621.3737 — https://support.microsoft.com/help/5039212
10.0.25398.950 — https://support.microsoft.com/help/5039236
10.0.10240.20680 — https://support.microsoft.com/help/5039225
10.0.14393.7070 — https://support.microsoft.com/help/5039214
6.0.6003.22720 — https://support.microsoft.com/help/5039245
6.0.6003.22720 — https://support.microsoft.com/help/5039266
6.1.7601.27170 — https://support.microsoft.com/help/5039289
6.1.7601.27170 — https://support.microsoft.com/help/5039274
6.2.9200.24919 — https://support.microsoft.com/help/5039260
6.3.9600.22023 — https://support.microsoft.com/help/5039294