This issue is because of an unsafe use of ForceIncomingString() in the addon. Each
and every use of this function should be wrapped in htmlspecialchars() to avoid XSS
attacks.
Edit files the files default.php library/Function.TagThis.php and make change all
instances of ForceIncomingString([...]) to
htmlspecialchars(ForceIncomingString([...])) and the code should be safe.
December 2009