Windows DNS Server Remote Code Execution Vulnerability

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Exploitation requires specific conditions, including particular network configurations and timing conditions, and has only been observed in limited scenarios. This means an attacker cannot reliably exploit the issue in all environments and may need favorable setup or circumstances for it to work.

How could an attacker exploit this vulnerability?
An unauthenticated attacker could exploit this vulnerability by sending a specially crafted packet to an affected service over the network. Successful exploitation could allow the attacker to execute code on the target system. No authentication or user interaction is required.

Security updates
10.0.17763.9121 — https://support.microsoft.com/help/5120238
10.0.20348.5499 — https://support.microsoft.com/help/5120242
10.0.20348.5440 — https://support.microsoft.com/help/5120229
10.0.26100.33296 — https://support.microsoft.com/help/5120233
10.0.26100.33222 — https://support.microsoft.com/help/5120228
10.0.14393.9418 — https://support.microsoft.com/help/5120418