Earlier today, Mt.Gox released a press release highlighting the “Transaction Malleability" issue with the Bitcoin protocol. Gavin Andresen, Lead Developer of the Bitcoin protocol later released a statement confirming that this is not a problem with the Bitcoin protocol, but is a challenge for creators of bitcoin wallet software (like Coinbase).
The malleability issue would allow an attacker to change the identifier of a transaction (but not the sender or recipient of bitcoin, amounts, or other information). If not accounted for carefully, this could lead some wallets to duplicate transactions.
After conducting a review of our wallet software, we could not find any instances of such an attack being used. We also looked into the technical details of the transaction malleability issue and just this morning added additional security measures to our software to further prevent such an attack. From our current analysis, there weren’t any users affected by this issue, but we’ll continue to monitor transactions to make sure. If you have any questions about a transaction on your account you can contact support.
Bitcoin is a truly exciting space to be in. Every day, more and more consumers and merchants are experiencing the value of bitcoin - simple, instant transactions - exactly what payments should be in the age of the Internet. With nearly 1M consumer wallets and over 23,000 merchants on our platform, Coinbase will continue to stay vigilant and do everything we can to make Bitcoin as easy as possible for customers.