It is nice to see that Coinbase is working proactively to prevent hacks and that they are working closely with other reputable entities to prevent "holes" in their system.
It's nothing unusual, people in software, even direct competitors, generally are very responsible and helpful towards each other when it comes to security holes - this is because there are very deep dependency connections, and vulnerability in one program can make thousands of others vulnerable. Remember how Bcash developers privately disclosed a dangerous Bitcoin bug?
In any way, plugging the same "holes" in our own browsers with a update is never a bad idea, because they can easily use the same hole to gather information from users of Coinbase.
The hackers could have gone for a mass attack against Coinbase and other exchange users, but in that case the hole would be patched very quickly, instead they choose to make a targeted attack, but luckily it was stopped (according to Coinbase).
