Mozilla Thunderbird users should be aware of a recently published update. The group released version 22.214.171.124 of the e-mail client today, for Windows and Mac, to address some potential security flaws. Only two of them were rated as critical, and one would only be of concern if you use Thunderbird as a newsreader.
The most dangerous of the plugged holes was a buffer overflow involving UTF-8 URLs, which could theoretically be used to compromise a system through the use of maliciously crafted URLs in messages. Some other minor issues have been corrected as well. You can get the update here.