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 create or delete files in the security context of the “NT AUTHORITY\ LOCAL SERVICE” account.

Security updates
10.0.17763.5696 — https://support.microsoft.com/help/5036896
10.0.20348.2402 — https://support.microsoft.com/help/5036909
10.0.22000.2899 — https://support.microsoft.com/help/5036894
10.0.19044.4291 — https://support.microsoft.com/help/5036892
10.0.22621.3447 — https://support.microsoft.com/help/5036893
10.0.25398.830 — https://support.microsoft.com/help/5036910
10.0.10240.20596 — https://support.microsoft.com/help/5036925
10.0.14393.6897 — https://support.microsoft.com/help/5036899
6.0.6003.22618 — https://support.microsoft.com/help/5036932
6.0.6003.22618 — https://support.microsoft.com/help/5036950
6.1.7601.27067 — https://support.microsoft.com/help/5036967
6.1.7601.27067 — https://support.microsoft.com/help/5036922
6.2.9200.24821 — https://support.microsoft.com/help/5036969
6.3.9600.21924 — https://support.microsoft.com/help/5036960