Firefox 31 for all supported platforms, addressing 11 vulnerabilities in total, three of which are marked critical that could have been exploited by hackers to mount remote code execution attacks. Mozilla Firefox recommends its users to install the security update as soon as possible, warning that the three critical vulnerabilities discovered in its browser could be exploited by attackers and leverage them to “run attacker code and install software” Mozilla also addresses two high rated vulnerabilities that cause a potential danger, as they could be used by an attacker to fetch users’ personal and sensitive information from other websites they visit.
Source: https://thehackernews.com/2014/07/firefox-31-mozilla-releases-security_22.html

