The rumor does not fit it into the transaction malleability scheme, confirmed to be a fact by foundation people.
All big withdrawals were checked manually,Gox has tight withdrawal limits on unverified accounts(on verified in fact too).
Therefore stealing 750k is i think iMPOSSIBLE.
Nobody said that they lost 750k BTC to transaction malleability. gmaxwell pointed out a few days back that it was possible that they'd lost more than they claimed to that issue but it was far from their only problem.
We have no idea when MtGox was last independently audited. It's entirely possible that it's only in trying to determine their losses due to the transaction malleability issue that they've looked far enough into their accounts to uncover other losses of which they were previously unaware. Small companies, in particular, have a bad habit of not looking below the surface often enough.
Huge financial institutions have constant checks and balances in place, spend billions on infrastructure, and still incur losses. It's all too easy to believe that MtGox had infrastructure totally insufficient for keeping track of their true financial situation.
Well, I guess everyone already read the joint statement from the other exchanges, are there any confirmations on how big is the damage?
MtGox hasn't even acknowledged the latest accusations yet. They'd be foolish to issue any public statement without expert legal advice at this point, so I wouldn't expect anything definitive any time soon unless it's a public statement saying that they're filing for insolvency protection.