Apple's Safari among browsers taken down at Pwn2Own day 2

South Korean security researcher Jung Hoon Lee toppled Safari with a use-after-free vulnerability, according to Threatpost. Lee was then able to bypass Safari's sandbox thanks to an uninitialized stack pointer, with the combined exploits netting him some $50,000 in prize money.

It seems likely that Lee's use-after-free attack was the catalyst for Tuesday's release of Safari 8.0.4, 7.1.4, and 6.2.4, which brought security fixes to the browser on Yosemite, Mavericks, and Mountain Lion, though that has not been confirmed. Apple said that the updates addressed "multiple memory corruption issues" in WebKit.

Meanwhile, Chrome fell thanks to a buffer overflow condition, Firefox went down after an out-of-bounds read/write vulnerability, and a time-of-check to time-of-use flaw took Internet Explorer out.

The Pwn2Own contest is held every year in conjunction with CanSecWest, an annual information security conference in Vancouver. Researchers often use the venue to disclose new exploits, which are developed for months in advance.

During Pwn2Own, contestants have 30 minutes to exploit browsers using remote code execution. The exploits must run without any input from the user apart from browsing to a maliciously-crafted website.

Successful hacks earn their creators prize money, with those that involve substantial privilege escalation earning even more. Lee won a total of $225,000 in prizes during the two-day competition.