Exploit vendor VUPEN disclosed details on a Firefox vulnerability it brought to this year s Pwn2Own contest. The bug was patched in March, one week after the contest. Firefox was popped four times during the Canadian hacker festival accounting for a quarter of the $800,000-plus in prize money handed out over the course of two days. Mozilla patched the four Firefox zero-day vulnerabilities within a week of their disclosure to the vendor during the contest, but details on the remaining bugs have yet to be released.
Source: https://threatpost.com/vupen-discloses-details-of-patched-firefox-pwn2own-zero-day/106213/