The first day of Pwn2Own 2021 contest saw contestants win $440,000 after successfully exploiting previously unknown vulnerabilities to hack Microsoft’s Windows 10 OS, the Exchange mail server, and the Teams communication platform. The first to fall was Microsoft Exchange in the Server category after the Devcore team achieved remote code execution on an Exchange server by chaining together an authentication bypass and a local privilege escalation to take over the server. The team earned $200,000 and $400,000 in cash and prizes.
Source: https://www.bleepingcomputer.com/news/security/microsofts-windows-10-exchange-and-teams-hacked-at-pwn2own/