Common language specific pitfalls

Common language-specific pitfalls:

 PHP specific pitfalls:
   File inclusion by remote and local 
   Situationally bad sanitizing:
    addslashes()
    htmlspecialchars()
    mysql_real_escape_string()
 Perl specific pitfalls:
   Command injection with open()      
 Python specific pitfalls:
   Urllib opens/follows file:// resource location response headers   (Python)
 Ruby (eruby and rails) specific pitfalls:
   attr_protected
   CGI.EscapeHTML()