Well Eddy, we could even be somewhat more precise and bet on this wordpress theme - themes/twentyten/ -
and it is a truly a good candidate to get us into trouble.
Read how that came backdoored, yep, by the developer I mean: http://wordpress.org/support/topic/security-issue-with-twentyten
So with free themes we have to be extremely cautious what we are actually installing :
polonus