Microsoft Office SharePoint Tampering Vulnerability

How could an attacker exploit this vulnerability?
An authenticated attacker with access to an affected SharePoint form could submit specially crafted session data to the server. Successful exploitation could allow the attacker to alter trusted application state and cause unauthorized backend actions; user interaction is not required.

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 have a deep understanding of the system and the ability to manipulate its components to trigger a specific condition. Successful exploitation is not guaranteed and depends on a combination of factors that may include the environment, system configuration, and the presence of additional security measures.

Security updates
16.0.19725.20522 — https://support.microsoft.com/help/5002893