ASP.NET Core SignalR and Visual Studio Information Disclosure Vulnerability

What type of information could be disclosed by this vulnerability? This vulnerability makes it possible to listen to any group or user with a specially crafted group/username. By exploiting this vulnerability, the attacker can now receive messages for group(s) that they are unauthorized to view.

According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is information disclosure? The attack itself is carried out locally. For example, when the score indicates that the Attack Vector is Local (AV:L) and User Interaction is Required (UI:R), this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and run a malicious application. This could lead to a local attack on the user's device which could leak data.