HEVC Video Extensions Remote Code Execution Vulnerability

According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?
The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally.
For example, when the score indicates that the Attack Vector is Local and User Interaction is Required, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer.

How can I check if the update is installed?
If your device manufacturer preinstalled this app, package versions 2.0.51121.0 and later contain this update.
If you purchased this app from the Microsoft Store, package versions 2.0.51122.0 and later contain this update.
You can check the package version in PowerShell:
Get-AppxPackage -Name Microsoft.HEVCVideoExtension*

What is the difference between HEVC Video Extension and HEVC Video Extensions?
HEVC Video Extension is available to consumers and HEVC Video Extensions is used by device OEMs.

Security updates
2.0.51122.0 — https://support.microsoft.com/en-us/account-billing/get-updates-for-apps-and-games-in-microsoft-store-a1fe19c0-532d-ec47-7035-d1c5a1dd464f