Just perform a normal system update in order to get the new version
On March 12, Canonical published details about Thunderbird vulnerabilities for its Ubuntu 12.10, Ubuntu 12.04 LTS, Ubuntu 11.10, and Ubuntu 10.04 LTS operating systems in a security notice.According to Canonical, Thunderbird could be made to crash or run programs as your login..
A previous update, USN-1758-1, fixed vulnerabilities in Firefox. This update provides the corresponding update for Thunderbird.
It was discovered that Firefox contained a memory safety issue. If a user was tricked into opening a specially crafted page with the HTML editor, a remote attacker could exploit this to execute arbitrary code with the privileges of the user invoking the program.
For a more detailed description of the security problems, you can visit Canonical's security notification.
Users can simply fix the security flaws by upgrading the operating systems to the Thunderbird package, specific to each distribution.
A normal system update, executed with the Update Manager, will implement all the necessary changes. After a standard system update, you will need to restart Thunderbird.
Users can also download Mozilla Thunderbird 17.0.4 right now from Softpedia.