Project Zero, Google’s zero-day bug-hunting team, discovered a group of hackers that used 11 zero-days in attacks targeting Windows, iOS, and Android users within a single year. The hackers used a couple of dozen websites hosting two exploit servers, each of them targeting iOS and Windows or Android users. The attacks ran two separate campaigns, in February and October 2020, with seven of the attacks using n-day exploits. Each of the exploits revealed an expert understanding of the vulnerability being exploited and exploit development.
Source: https://www.bleepingcomputer.com/news/security/hacking-group-used-11-zero-days-to-attack-windows-ios-android-users/