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
10.0.17763.5576 — https://support.microsoft.com/help/5035849
10.0.20348.2340 — https://support.microsoft.com/help/5035857
10.0.20348.2333 — https://support.microsoft.com/help/5035959
10.0.22000.2836 — https://support.microsoft.com/help/5035854
10.0.19044.4170 — https://support.microsoft.com/help/5035845
10.0.22621.3296 — https://support.microsoft.com/help/5035853
10.0.25398.763 — https://support.microsoft.com/help/5035856
10.0.10240.20526 — https://support.microsoft.com/help/5035858
10.0.14393.6796 — https://support.microsoft.com/help/5035855
6.0.6003.22567 — https://support.microsoft.com/help/5035920
6.0.6003.22567 — https://support.microsoft.com/help/5035933
6.1.7601.27017 — https://support.microsoft.com/help/5035888
6.1.7601.27017 — https://support.microsoft.com/help/5035919
6.2.9200.24768 — https://support.microsoft.com/help/5035930
6.3.9600.21871 — https://support.microsoft.com/help/5035885