Security is no joke indeed, thanks for reporting.
The glitch has been fixed. We review any single transaction manually at the moment anyway.
Our commitment is to ensure maximum stability, even if we have to restore damage.
Still easy to exploit.
Malicious page has an 1px * 1px iframe displaying the withdraw page, populates and posts form through javascript with the added bonus that it can parse the DOM to figure out your exact (well floating point exact XD) BTC balance before withdrawing it.
* davout heads to bitcoin-central.net to add a PIN code

Yup. I'm adding a framebreaker to Ubitex.org (although since I don't handle money, not nearly as bad.)