Microsoft Edge (Chromium-based) Elevation of Privilege Vulnerability

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
For an attacker to exploit this vulnerability, they would need to have knowledge of a specific operation that triggers a memory allocation failure, specifically a use after free.

What privileges could be gained by an attacker who successfully exploited the vulnerability?
An attacker could use this vulnerability to elevate privileges from a Low Integrity Level in a contained ("sandboxed") execution environment to a Medium Integrity Level. Please refer to AppContainer isolation and Mandatory Integrity Control for more information.

According to the CVSS metric, a successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability?
This vulnerability could lead to a browser sandbox escape.

There are multiple update packages available for some of the affected software. Do I need to install all the updates listed in the Security Updates table for the software?
Yes. Customers should apply all updates offered for the software installed on their systems.

Security updates
153.0.4234.46 — https://docs.microsoft.com/en-us/DeployEdge/microsoft-edge-relnotes-security