If you do not accept zero-confirmation transactions this vulnerability does not affect you.
However if you do be advised that a previously unknown coin-stealing attack has been found that allows zero-confirmation transactions to be double-spent with a trivial amount of effort and without having to have access to any mining capacity.
Details will be release as soon as a patch is ready. In the meantime do not accept any transaction without at least one confirmation unless you fully trust the sender not to defraud you.
Mods: please copy this to important announcements.
