The flaw can potentially be used to reveal not just the contents of a secured-message, such as a credit-card transaction over HTTPS, but the primary and secondary SSL keys themselves. This data could then, in theory, be used as a skeleton keys to bypass secure servers without leaving a trace that a site had been hacked.
This bug not a problem with OpenSSL’s inherent design. It’s an implementation problem. That is to say it the result of a programming mistake. There is already a fix available for the problem for the 1.01 program in OpenSSL 1.0.1g. Work is proceeding rapidly for a pair of the 1.02-beta line.