Thanks to mobile devices like my iPhone and iPad I received a message in my holidays concerning a vulnarability issue with the TimThumb image resizer script that is used in my themes. Check this blog post for more information.
Due to the fact that I´m on a holiday trip I cannot update my themes in short term so I provide this little workaround to you. Either you open the file timthumb.php which is normally located in the /lib/scripts or /tools/scripts subfolder of PRiNZ themes (depending on the version you have) and look for this line
$allowedSites = array( 'flickr.com', 'picasa.com', 'blogger.com', 'wordpress.com', 'img.youtube.com', );
remove the entries in the array so it looks like this instead
$allowedSites = array();
This should fix the issue. You can also download a newer version of TimThumb here and replace the whole old file with it. This is untested by me but it should work. Always make a backup of your old files before you change something. I guess it also makes sense not to use TimThumb in your themes options and use the WordPress own post thumbnail function for the image handling. I will update all my themes when I´m back from my vacation.