Description
Import variables from an array into the current symbol table.
If flags is not specified, it is assumed to be EXTR_OVERWRITE.
EXTR_OVERWRITE
If there is a collision, overwrite the existing variable.
The danger is that any state variables set before the extract($_...)'s can be overwritten arbitrarily. This also makes it essential that any and every variable is instantiated prior to any use.
Comments
The real problem is: "extract($_POST); extract($_GET); extract($_COOKIE);"
For more information on extract: http://www.php.net/extract
Docu on extract():
The danger is that any state variables set before the extract($_...)'s can be overwritten arbitrarily. This also makes it essential that any and every variable is instantiated prior to any use.