How secure are popular open source web frameworks? 

I am particularly interested in popular frameworks like Rails and DJango.

If I am building a site which is going to do heavy e-commerce, is it Ok to use
frameworks like DJango and [Satchmo](http://www.satchmoproject.com)? 

Is security compromised because their open architecture ?

I know being OS does not mean being down right open to hackers, Linux uses superb authentication mechanism, but web is a different game.

What can be done in this regard? 

**UPDATE:**

Thanks for answers guys.

I understand that I will have to find a suitable hosting service for a secure e-commerce application and that additional layers of security will be needed. 

I understand that Django and Rails have been designed keeping security aspects in mind, the most common form attacks like XSS, Injections etc. 
([Django book](http://www.djangobook.com/en/1.0/) has a ch on [Security](http://www.djangobook.com/en/1.0/chapter19/))

I was expecting comments from security Gurus. If you are a security Guru, would you recommend an important site, which is likely going to be popular, to be built on DJango
or Rails?