Mozilla released Firefox 52.0.1 to fix a security flaw that came to light in Pwn2Own 2017 hacking contest. The Chaitin Security Research Lab from Beijing, China, successfully exploited Firefox with an integer overflow and escalated privileges through an uninitialized buffer in the Windows kernel to get system-level privileges. The most creative exploit chain pocketed researchers $105,000 in one go. The team who discovered the bug finished third behind Qihoo’s 360 Security team and Tencent Security’s Team Sniper.
Source: https://www.bleepingcomputer.com/news/security/it-took-mozilla-22-hours-to-patch-a-firefox-vulnerability-discovered-at-pwn2own/