Ubuntu Security Notice 2656-2 – USN-2656-1 fixed vulnerabilities in Firefox for Ubuntu 14.04 LTS and later releases. This update provides the corresponding update for Ubuntu 12.04 LTS. Karthikeyan Bhargavan discovered that NSS incorrectly handled state transitions for the TLS state machine. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to skip the ServerKeyExchange message and remove the forward-secrecy property. Looben Yan discovered 2 use-after-free issues when using XMLHttpRequest in some circumstances. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service via application crash, or execute arbitrary code with the privileges of the user invoking Firefox. Various other issues were also addressed.