A 'highly critical' vulnerability has been found in the Opera web browser which could be exploited to remotely compromise a user's system. The flaw is caused when Opera uses already freed memory to parse BitTorrent headers, and can lead to an invalid object pointer being de-referenced.
http://www.neowin.net/index.php?act=view&id=41552
You were right Mir, some features of Opera can't be reproduced in Firefox :) </in-joke>
Anyway, be careful guys and gals!