One problem related to ignition has been reported for the 2012 Nissan Altima. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 Nissan Altima based on all problems reported for the 2012 Altima.
If you leave the key outside the vehicle and it is touching the vehicle the push button ignition will acknowledge the key and start the vehicle. According to the manual the key must be with you (inside) in order for the vehicle to start. There is no warning stating otherwise. This is a personal security and safety issue.