Windows Telephony Server Elevation of Privilege Vulnerability

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.

What privileges could be gained by an attacker who successfully exploited the vulnerability?
An attacker who successfully exploited this vulnerability could execute code in the security context of the “NT AUTHORITY\Network Service” account.

Security updates
10.0.17763.5206 — https://support.microsoft.com/help/5033371
10.0.20348.2159 — https://support.microsoft.com/help/5033118
10.0.20348.2144 — https://support.microsoft.com/help/5033464
10.0.22000.2652 — https://support.microsoft.com/help/5033369
10.0.19041.3803 — https://support.microsoft.com/help/5033372
10.0.22621.2861 — https://support.microsoft.com/help/5033375
10.0.25398.584 — https://support.microsoft.com/help/5033383
10.0.10240.20345 — https://support.microsoft.com/help/5033379
10.0.14393.6529 — https://support.microsoft.com/help/5033373
6.0.6003.22413 — https://support.microsoft.com/help/5033422
6.0.6003.22413 — https://support.microsoft.com/help/5033427
6.1.7601.26864 — https://support.microsoft.com/help/5033433
6.1.7601.26864 — https://support.microsoft.com/help/5033424
6.2.9200.24614 — https://support.microsoft.com/help/5033429
6.3.9600.21715 — https://support.microsoft.com/help/5033420