Mozilla released the latest version of its Firefox 35, fixing nine vulnerabilities, including three critical bugs that could have led to a crash or sandbox bypass. One of those critical bugs was a sandbox escape discovered by security researcher Nils, a researcher at MWR InfoSecurity in the U.K., found a way to break out of the Gecko Media plugin (GMP) sandbox on Windows systems. The update also remedies a read-after-free bug in WebRTC that stems from the way tracks are handled.
Source: https://threatpost.com/mozilla-patches-nine-vulnerabilities-with-firefox-35/110486/