On February 19, Canonical published details about a Firefox regression for its Ubuntu 13.10, Ubuntu 12.10, and Ubuntu 12.04 LTS operating systems.According to Canonical, a previous update, USN-2102-1, introduced a regression in Firefox.
According to the notification, USN-2102-1 fixed vulnerabilities in Firefox. The update introduced a regression that could make Firefox crash under some circumstances. This new build fixes the problem.
For a more detailed description of the problems, you can visit Canonical's security notification.
Users can simply fix the security flaws by upgrading their operating systems to the latest Firefox package specific to each distribution.
A normal system update, executed with the Update Manager, will implement all the necessary changes. A complete system restart is not needed, but you will have to restart the application.
Alternatively, you can download Mozilla Firefox 27.0.1 right now from Softpedia.