https://bitcoinfoundation.org/blog/?p=422
According to this description of transaction malleability, you will only be affected by the transaction malleability bug if you make frequent transactions in a small amount of time. So, that begs the question, in order for transaction malleability not to affect you, how long must you wait between transactions?
Thanks,
The problem described in the Foundations blog post involves spending unconfirmed change. That is, I have 10 BTC in my wallet (in one output), I send 2 BTC to someone else, get a change transaction for 8 BTC back to my wallet. If I want to spend this 8 BTC before it is confirmed, a transaction malleability attack may mess things up.
So how long do you have to wait? Until the original transaction is included in a block.
Note that this only applies if you want to make a transaction using a change-output that is unconfirmed. You can make many transactions close after eachother as long as they don't use eachothers change-outputs.