What is a level 7 exploit?

Excuse me, could you please elaborate on what exactly a level 7 exploit refers to in the context of cybersecurity and cryptocurrency? I'm curious to understand the severity and potential consequences of such an exploit, as well as how it might differ from other levels of exploits. Is there a standardized scale or classification system that defines the different levels, and if so, what criteria are used to determine the severity of an exploit? Thank you for your time and expertise in this matter.