Is it necessary to validate the source of POST's?

[Vigilante]

I've been writing a portal system for my site and someone has warned me that my site is vulnerable because forms not on my site could send my scripts info. I was wondering if anyone versed in cgi security could tell me what kind of attacks I am risking by not checking the source of a POST.

To me, this doesn't seem like a problem but does people making their own forms and passing my scripts extra get or post variables particularly present a problem

[Mordecai]

Personally, I don't think it's a problem. You should definately validate what is being sent, but not so much where it was sent from.