Not all of them. One was a use after free, which isn't related to buffer overflows. Two other ones are not clear what they were caused by: By Mariusz Mlynski:

Not all of them. One was a use after free, which isn't related to buffer overflows. Two other ones are not clear what they were caused by: By Mariusz Mlynski: Against Mozilla Firefox, two vulnerabilities, one allowing privilege escalation within the browser and one bypassing browser security measures. http://h30499.www3.hp.com/t5/HP-Security-Research-Blog/Pwn2Own-results-for-Thursday-Day-Two/ba-p/6412622#.UyYOW9tx0xC http://h30499.www3.hp.com/t5/HP-Security-Research-Blog/Pwn2O... http://h30499.www3.hp.com/t5/HP-Security-Research-Blog/Pwn2Own-results-for-Wednesday-Day-One/ba-p/6410984#.UyYOXttx0xC http://h30499.www3.hp.com/t5/HP-Security-Research-Blog/Pwn2O...