It’s being called the biggest breach of all time and the mother of all breaches: COMB, or the Compilation of Many Breaches, contains more than 3.2 billion unique pairs of cleartext emails and passwords. While many data breaches and leaks have plagued the internet in the past, this one is exceptional in the sheer size of it. To wit, the entire population of the planet is at roughly 7.8 billion, and this is about 40% of that.
However, when considering that only about 4.7 billion people are online, COMB would include the data of nearly 70% of global internet users (if each record was a unique person). For that reason, users are recommended to immediately check if their data was included in the leak.