Microsoft Edge (Chromium-based) Security Feature Bypass Vulnerability

According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do? This vulnerability requires that a user have multiple browser instances open of the affected version of Microsoft Edge (Chromium-based), one of which is a specially crafted website hosted by the attacker. The user would need to access the URL of the malicious website and then click a popup displayed on that site.

According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of confidentiality (C:H), integrity (I:H), and (A:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability could lead to a full compromise of the browser.