Previously, Google has released an update for Nexus 4, which occurred in August, then a HTC One GE updated on September 11. Thus, the delay update for Galaxy S4 Google Edition came with a delay of a month, which is quite acceptable, considering how long to test the firmware and as he Samsung releases updates for its smartphones and tablets.
Vulnerability is exactly random number generation, which in turn is very important to generate the security key. Selected numbers were not truly random, so sometimes they were too predictable. It could even lead to the theft of real money, if you had access to them from your mobile device.