A backdoored version of Bitcoin wallet was planted by the attackers who gained access to the GitHub repository. As a result, those users who downloaded the infected version instead of the official one might have lost their private keys if they created new wallets using this malicious software.
Users who downloaded the compromised wallet during a window of 4.5 days may have their private keys compromises.
The attackers seem to have been able to access the version control system but not to sign on behalf of developers.