On October 31, Canonical announced that the new Mozilla Thunderbird had arrived in the official repositories for its Ubuntu 13.10, Ubuntu 13.04, Ubuntu 12.10, and Ubuntu 12.04 LTS operating systems.
According to the company, multiple memory safety issues have been discovered in Thunderbird. If a user was tricked into opening a specially crafted message with scripting enabled, an attacker could possibly exploit these to cause a denial of service via application crash, or potentially execute arbitrary code with the privileges of the user invoking Thunderbird.
For a more detailed description of these problems, you can visit Canonical's security notification.
Users can simply fix the security flaws by upgrading the operating systems to the latest Thunderbird package specific to each distribution.
A normal system update, executed with the Update Manager, will implement all the necessary changes. You won't need to reboot the computer, but you will have to restart Thunderbird.
Users can also download Mozilla Thunderbird 24.1.0 right now from Softpedia.